Polymerization Process for Producing Bimodal Polymers

ABSTRACT

Catalyst compositions comprising a first metallocene compound, a second metallocene compound, an activator-support, and an organoaluminum compound are provided. An improved method for preparing cyclopentadienyl complexes used to produce polyolefins is also provided.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of co-pending U.S. patentapplication Ser. No. 12/357,007, filed on Jan. 21, 2009, now U.S. Pat.No. ______, which is a divisional application of U.S. patent applicationSer. No. 11/705,695, filed on Feb. 12, 2007, now U.S. Pat. No.7,521,572, which is a divisional application of U.S. patent applicationSer. No. 11/208,077, filed on Sep. 15, 2005, now U.S. Pat. No.7,226,886, the disclosures of which are incorporated herein by referencein their entirety.

TECHNICAL FIELD OF THE INVENTION

This invention relates to the field of olefin polymerization catalysis,catalyst compositions, methods for the polymerization andcopolymerization of olefins, polyolefins, and film and pipe resinsformed therefrom, particularly using a supported catalyst composition.The present invention also relates to the fields of organic synthesisand organometallic synthesis, including synthetic methods forhalf-metallocenes.

BACKGROUND OF THE INVENTION

Presently, a variety of polyethylene (PE) resins can be used to producehigh stiffness pipe used in water, gas, and other fluid transportapplications. Polyethylene pipe classified as PE-100, MRS 10, or ASTMD3350 typical cell classification 345566C is especially desirable foruse under conditions requiring higher pressure ratings. To obtain aPE-100 classification, PE-100 pipe is required to meet certain standardsspecifying stiffness, resistance to slow crack growth, resistance tochemical attack, and low-temperature toughness (expressed as rapid crackpropagation). Further, such pipe must meet a deformation standard thatis determined under pressure at elevated temperatures. It is alsodesirable for PE-100 pipe to exhibit toughness, for example, where thepipe is buried underground or where the pipe is used to transport coarseor abrasive slurries. Accordingly, there is a need for a resin and aPE-100 pipe made therefrom that has improved physical properties andimpact resistance properties.

With conventional processes and resins formed using metallocene catalystsystems, there is a trade off between high stiffness and highenvironmental stress cracking resistance (ESCR). While either highstiffness or high ESCR items can be manufactured, conventional processesdo not produce items having both high stiffness and high ESCR.

SUMMARY OF THE INVENTION

The present invention generally relates to a catalyst compositionincluding two metallocene compounds, an activator, and a cocatalyst. Thepresent invention further relates to processes for producing such acatalyst composition, polymerization processes, and polymers producedtherefrom. The metallocene compounds are combined with an activator, analuminum alkyl compound, and olefin monomers to produce a polyolefinhaving a bimodal molecular weight distribution. The resulting polymersfeature an outstanding balance of stiffness and slow crack growthresistance. Additionally, the polymers produced according to the presentinvention have excellent impact strength.

In accordance with the present invention, the two metallocene compoundsare selected such that the polymers produced therefrom have twodistinctly different molecular weights. One of the metallocenes,typically a tightly bridged metallocene containing a substituent thatincludes a terminal olefin, produces a high molecular weight component.Another metallocene, which typically is not bridged and often is moreresponsive to hydrogen than the first metallocene, produces a lowmolecular weight component of the resin.

According to one aspect of the present invention, a catalyst compositioncomprises a first metallocene compound, a second metallocene compound,an activator-support, and an organoaluminum compound. The firstmetallocene compound has the formula:

(X¹)(X²R¹ ₂)(X³)(X⁴)M¹;

wherein (X¹) is cyclopentadienyl, indenyl, or fluorenyl, (X²) isfluorenyl, and (X¹) and (X²) are connected by a disubstituted bridginggroup comprising one atom bonded to both (X¹) and (X²), wherein the atomis carbon or silicon. A first substituent of the disubstituted bridginggroup is an aliphatic or aromatic group having from 1 to about 20 carbonatoms. A second substituent of the disubstituted bridging group is asaturated or unsaturated aliphatic group having from 3 to about 10carbon atoms. R¹ is H or an alkyl group having from 1 to about 4 carbonatoms, (X³) and (X⁴) independently are a halide, and M¹ is Zr or Hf. Thefirst substituent of the disubstituted bridging group may be phenyl ormethyl. The second substituent of the disubstituted bridging group maybe butenyl, pentenyl, or hexenyl.

According to this and other aspects of the present invention, the firstmetallocene may be:

or any combination thereof.

The second metallocene compound has the formula:

wherein R² is H or —CH₃; R³ is CH₂═CHCH₂—, CH₂═CH(CH₂)₂—, Ph(CH₂)₃—,CH₃(CH₂—)₃, or H; X⁵ and X⁶ independently are a halide; and M² is Zr orHf.

According to this and other aspects of the present invention, the ratioof the first metallocene compound to the second metallocene compound maybe from about 1:10 to about 10:1. According to other aspects of thepresent invention, the ratio of the first metallocene compound to thesecond metallocene compound may be from about 1:5 to about 5:1.According to yet other aspects of the present invention, the ratio ofthe first metallocene compound to the second metallocene compound may befrom about 1:2 to about 2:1.

The organoaluminum compound used with the present invention may have theformula:

(R²)₃Al;

wherein (R²) is an aliphatic group having from 2 to about 6 carbonatoms. In some instances, (R²) is an ethyl group, a propyl group, abutyl group, a hexyl group, or an isobutyl group.

According to another aspect of the present invention, a catalystcomposition comprises an ansa-metallocene compound, an unbridgedmetallocene compound, an activator-support, and an organoaluminumcompound. The ansa-metallocene compound is:

or a combination thereof.

The unbridged metallocene compound is:

or a combination thereof.

According to this and other aspects of the present invention, theactivator-support may be fluorided alumina, chlorided alumina, bromidedalumina, sulfated alumina, fluorided silica-alumina, chloridedsilica-alumina, bromided silica-alumina, sulfated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, a pillared clay, or anycombination thereof.

The catalyst composition of the present invention may thus comprise afirst metallocene compound, a second metallocene compound, anactivator-support, and at least one organoaluminum compound, wherein:

(a) the first metallocene compound is:

(b) the second metallocene compound is:

(c) the activator-support is sulfated alumina;

(d) the organoaluminum compound is tri-n-butylaluminum.

The present invention also contemplates a process for polymerizingolefins in the presence of a catalyst composition. The process comprisescontacting the catalyst composition with at least one type of olefinmonomer under polymerization conditions, where the catalyst compositioncomprises an ansa-metallocene compound, an unbridged metallocenecompound, an activator-support, and an organoaluminum compound. Theansa-metallocene compound has the formula:

(X¹)(X²R¹ ₂)(X³)(X⁴)M¹;

wherein (X¹) is cyclopentadienyl, indenyl, or fluorenyl, (X²) isfluorenyl, and (X¹) and (X²) are connected by a disubstituted bridginggroup comprising one atom bonded to both (X¹) and (X²), wherein the atomis carbon or silicon. A first substituent of the disubstituted bridginggroup is an aliphatic or aromatic group having from 1 to about 20 carbonatoms. A second substituent of the disubstituted bridging group is asaturated or unsaturated aliphatic group having from 3 to about 10carbon atoms. R¹ is H or an alkyl group having from 1 to about 4 carbonatoms, (X³) and (X⁴) independently are a halide, and M¹ is Zr or Hf.

The unbridged metallocene has the formula:

wherein R² is H or —CH₃; R³ is CH₂═CHCH₂—, CH₂═CH(CH₂)₂—, Ph(CH₂)₃—,CH₃(CH₂—)₃, or H; X⁵ and X⁶ independently are a halide; and M² is Zr orHf.

The present invention further contemplates a process for producing acatalyst composition comprising contacting a first metallocene compound,a second metallocene compound, an activator-support, and at least oneorganoaluminum compound. The first metallocene compound has the formula:

(X¹)(X²R¹ ₂)(X³)(X⁴)M¹;

wherein (X¹) is cyclopentadienyl, indenyl, or fluorenyl, (X²) isfluorenyl, and (X¹) and (X²) are connected by a disubstituted bridginggroup comprising one atom bonded to both (X¹) and (X²), wherein the atomis carbon or silicon. A first substituent of the disubstituted bridginggroup comprises an aliphatic or aromatic group having from 1 to about 10carbon atoms. A second substituent of the disubstituted bridging groupis a saturated or unsaturated aliphatic group having from 3 to about 10carbon atoms. R¹ is H or an alkyl group having from 1 to about 4 carbonatoms, (X³) and (X⁴) independently are a halide, and M¹ is Zr or Hf.

The second metallocene has the formula:

wherein R² is H or —CH₃; R³ is CH₂═CHCH₂—, CH₂═CH(CH₂)₂—, Ph(CH₂)₃—,CH₃(CH₂—)₃, or H; X⁵ and X⁶ independently are a halide; and M² is Zr orHf.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 represents the NMR spectrum for the Zr[η-C₅H₄-(nBu)]Cl₃ formedaccording to Example 1.

FIG. 2 represents the NMR spectrum for the Zr[η-O₅H₄-(nBu)]Cl₃ formedaccording to Example 2.

FIG. 3 represents a comparison of the level of monomer incorporationusing metallocene compounds of the present invention with that ofbis-indenyl zirconium dichloride.

FIG. 4 represents the molecular weight distribution of an exemplarypolymer prepared according to this invention.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. To the extent that any definition or usage provided by anydocument incorporated herein by reference conflicts with the definitionor usage provided herein, the definition or usage provided hereincontrols.

The term “polymer” is used herein to mean homopolymers comprisingethylene and copolymers of ethylene and another olefinic comonomer.“Polymer” is also used herein to mean homopolymers and copolymers of anyother polymerizable monomer disclosed herein.

The term “cocatalyst” is used generally herein to refer to theorganoaluminum compounds that may constitute one component of thecatalyst composition. Additionally, “cocatalyst” refers to the optionalcomponents of the catalyst composition including, but not limited to,aluminoxanes, organoboron compounds, organozinc compounds, or ionizingionic compounds, as disclosed herein. The term “cocatalyst” may be usedregardless of the actual function of the compound or any chemicalmechanism by which the compound may operate. In one aspect of thisinvention, the term “cocatalyst” is used to distinguish that componentof the catalyst composition from the metallocene compound.

The term “fluoroorgano boron compound” is used herein with its ordinarymeaning to refer to neutral compounds of the form BY₃. The term“fluoroorgano borate compound” also has its usual meaning to refer tothe monoanionic salts of a fluoroorgano boron compound of the form[cation]⁺[BY₄]⁻, where Y represents a fluorinated organic group. Forconvenience, fluoroorgano boron and fluoroorgano borate compounds aretypically referred to collectively by “organoboron compounds”, or byeither name as the context requires.

The term “precontacted” mixture is used herein to describe a firstmixture of catalyst components that are contacted for a first period oftime prior to the first mixture being used to form a “postcontacted” orsecond mixture of catalyst components that are contacted for a secondperiod of time. Typically, the precontacted mixture describes a mixtureof metallocene compound (or compounds), olefin monomer, andorganoaluminum compound (or compounds), before this mixture is contactedwith the activator-support and optional additional organoaluminumcompound. Thus, precontacted describes components that are used tocontact each other, but prior to contacting the components in thesecond, postcontacted mixture. Accordingly, this invention mayoccasionally distinguish between a component used to prepare theprecontacted mixture and that component after the mixture has beenprepared. For example, according to this description, it is possible forthe precontacted organoaluminum compound, once it is contacted with themetallocene and the olefin monomer, to have reacted to form at least onedifferent chemical compound, formulation, or structure from the distinctorganoaluminum compound used to prepare the precontacted mixture. Inthis case, the precontacted organoaluminum compound or component isdescribed as comprising an organoaluminum compound that was used toprepare the precontacted mixture.

Similarly, the term “postcontacted” mixture is used herein to describe asecond mixture of catalyst components that are contacted for a secondperiod of time, and one constituent of which is the “precontacted” orfirst mixture of catalyst components that were contacted for a firstperiod of time. Typically, the term “postcontacted” mixture is usedherein to describe the mixture of the metallocene compound, olefinmonomer, organoaluminum compound, and chemically-treated solid oxide,formed from contacting the precontacted mixture of a portion of thesecomponents with any additional components added to make up thepostcontacted mixture. Generally, the additional component added to makeup the postcontacted mixture is the chemically-treated solid oxide, and,optionally, may include an organoaluminum compound the same or differentfrom the organoaluminum compound used to prepare the precontactedmixture, as described herein. Accordingly, this invention may alsooccasionally distinguish between a component used to prepare thepostcontacted mixture and that component after the mixture has beenprepared.

The term “metallocene”, as used herein, describes a compound comprisingtwo η⁵-cycloalkadienyl-type ligands in the molecule. Thus, themetallocenes of this invention are bis(η⁵-cyclopentadienyl-type ligand)compounds, wherein the η⁵-cycloalkadienyl portions includecyclopentadienyl ligands, indenyl ligands, fluorenyl ligands, and thelike, including partially saturated or substituted derivatives oranalogs of any of these. Possible substituents on these ligands includehydrogen, therefore the description “substituted derivatives thereof” inthis invention comprises partially saturated ligands such astetrahydroindenyl, tetrahydrofluorenyl, octahydrofluorenyl, partiallysaturated indenyl, partially saturated fluorenyl, substituted partiallysaturated indenyl, substituted partially saturated fluorenyl, and thelike. In some contexts, the metallocene is referred to simply as the“catalyst”, in much the same way the term “cocatalyst” is used herein torefer to the organoaluminum compound. Unless otherwise specified, thefollowing abbreviations are used: Cp for cyclopentadienyl; Ind forindenyl; and Flu for fluorenyl.

The terms “catalyst composition”, “catalyst mixture”, and the like donot depend upon the actual product resulting from the contact orreaction of the components of the mixtures, the nature of the activecatalytic site, or the fate of the aluminum cocatalyst, the metallocenecompound, any olefin monomer used to prepare a precontacted mixture, orthe chemically-treated solid oxide after combining these components.Therefore, the terms “catalyst composition”, “catalyst mixture”, and thelike may include both heterogeneous compositions and homogenouscompositions.

The term “hydrocarbyl” is used herein to specify a hydrocarbon radicalgroup that includes, but is not limited to aryl, alkyl, cycloalkyl,alkenyl, cycloalkenyl, cycloalkadienyl, alkynyl, aralkyl, aralkenyl,aralkynyl, and the like, and includes all substituted, unsubstituted,branched, linear, heteroatom substituted derivatives thereof.

The terms “chemically-treated solid oxide”, “solid oxideactivator-support”, “acidic activator-support”, “activator-support”,“treated solid oxide compound”, or simply “activator”, and the like areused herein to indicate a solid, inorganic oxide of relatively highporosity, which exhibits Lewis acidic or Brønsted acidic behavior, andwhich has been treated with an electron-withdrawing component, typicallyan anion, and which is calcined. The electron-withdrawing component istypically an electron-withdrawing anion source compound. Thus, thechemically-treated solid oxide compound comprises the calcined contactproduct of at least one solid oxide compound with at least oneelectron-withdrawing anion source compound. Typically, thechemically-treated solid oxide comprises at least one ionizing, acidicsolid oxide compound. The terms “support” and “activator-support” arenot used to imply these components are inert, and such components shouldnot be construed as an inert component of the catalyst composition.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention. The publications discussed above and throughout the text areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the inventors are not entitled to antedate such disclosure byvirtue of prior invention.

For any particular compound disclosed herein, any general structurepresented also encompasses all conformational isomers, regioisomers, andstereoisomers that may arise from a particular set of substituents. Thegeneral structure also encompasses all enantiomers, diastereomers, andother optical isomers whether in enantiomeric or racemic forms, as wellas mixtures of stereoisomers, as the context requires.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to new catalystcompositions, methods for preparing catalyst compositions, and methodsfor using the catalyst compositions to polymerize olefins. The presentinvention further is directed to a method of preparing cyclopentadienylcomplexes and a method of isolating such compounds as a solid.

In particular, the present invention relates to new catalystcompositions and methods of using such catalyst compositions to formpolyolefins having an excellent balance of stiffness and slow crackgrowth resistance. The catalyst composition includes at least twometallocenes. The first metallocene compound is used to produce a highmolecular weight component, and is generally a tightly bridgedmetallocene containing a substituent that includes a terminal olefin.The second metallocene, used to produce the low molecular weightcomponent, is generally not bridged and is more responsive to hydrogenthan the first metallocene. The metallocenes are combined with a solidactivator, an aluminum alkyl compound, and an olefin monomer to producethe desired bimodal polyolefin. It has been discovered that thebi-metallocene catalyst system of the present invention provides auseful combination of polyolefin properties, such as stiffness and slowcrack growth resistance, so the resin is suitable for blowing film,forming a pipe, and so forth.

According to one aspect of the present invention, a composition ofmatter is provided. The composition includes a first metallocenecompound, a second metallocene compound, an activator-support, and anorganoaluminum compound. According to other aspects, the presentinvention is directed to a catalyst composition, a catalyst compositionfor polymerizing olefins, a method of preparing a catalyst composition,a method of using a catalyst composition, and the like, in each caseencompassing a first metallocene compound, a second metallocenecompound, an activator-support, and an organoaluminum compound. Thepresent invention is directed further to a method for producingpolyolefins and films, and polyolefins and film produced therefrom.According to still another aspect, the present invention is directed toa method of preparing monocyclopentadienyl compounds that may be used toform metallocene compounds.

A. Catalyst Composition and Components

The present invention is directed to a catalyst composition including afirst metallocene compound, a second metallocene compound, anactivator-support, and an organoaluminum compound. The first metalloceneproduces a high molecular weight component, and is generally a tightlybridged metallocene containing a substituent that includes a terminalolefin. The second metallocene, used to produce the low molecular weightcomponent, is generally not bridged and is more responsive to hydrogenthan the first metallocene. The combination of metallocenes is used withan activator-support and an organoaluminum compound to form polyolefinshaving an excellent balance of stiffness and slow crack growthresistance.

Catalyst compositions including various combinations of thesemetallocenes including, but not limited to, at least one firstmetallocene compound, at least one second metallocene compound, and anycombination of more than one first metallocene compound, more than onesecond metallocene compound are also contemplated by this invention.Further, use of more than one activator-support and more than oneorganoaluminum compound is also contemplated.

1. The Metallocene Compounds

(a) The First Metallocene Compound

According to one aspect of the present invention, the first metallocenecompound is an ansa-metallocene compound having the formula:

(X¹)(X²R¹ ₂)(X³)(X⁴)M¹  (I);

wherein (X¹) is cyclopentadienyl, indenyl, or fluorenyl; (X²) isfluorenyl; (X¹) and (X²) are connected by a disubstituted bridging groupcomprising one atom bonded to both (X¹) and (X²), wherein the atom iscarbon or silicon; a first substituent of the disubstituted bridginggroup comprises an aliphatic or aromatic group having from 1 to about 10carbon atoms; a second substituent of the disubstituted bridging groupis a saturated or unsaturated aliphatic group having from 3 to about 10carbon atoms; R¹ is H or an alkyl group having from 1 to about 4 carbonatoms; (X³) and (X⁴) independently are a halide; and M¹ is Zr or Hf.

According to one aspect of the present invention, the first substituentof the disubstituted bridging group may be phenyl or methyl. The secondsubstituent of the disubstituted bridging group may be butenyl,pentenyl, or hexenyl. In this and other aspects, (X³) and (X⁴) may bethe same or different.

According to yet another aspect of the present invention, the firstmetallocene compound is an ansa-metallocene compound having the formula:

(X¹)(X²R¹ ₂)(X³)(X⁴)M¹;

wherein (X¹) is cyclopentadienyl, indenyl, or fluorenyl; (X²) isfluorenyl; (X¹) and (X²) are connected by a disubstituted bridging groupcomprising one atom bonded to both (X¹) and (X²), wherein the atom iscarbon or silicon; a first substituent of the disubstituted bridginggroup comprises an aliphatic or aromatic group having from 1 to about 6carbon atoms; a second substituent of the disubstituted bridging groupis a saturated or unsaturated aliphatic group having from 3 to about 6carbon atoms; R¹ is an alkyl group having from 1 to about 4 carbonatoms; (X³) and (X⁴) independently are a halide; and M¹ is Zr or Hf.

According to one aspect of the present invention, the first substituentof the disubstituted bridging group may be phenyl or methyl. Accordingto another aspect of the present invention, the second substituent ofthe disubstituted bridging group may be butenyl, pentenyl, or hexenyl.

Some examples of metallocene compounds that may be suitable for use asthe first metallocene compound in accordance with the present inventioninclude, but are not limited to:

or any combination thereof.

Additional examples of metallocene compounds that may be suitable foruse as the first metallocene compound in accordance with the presentinvention include, but are not limited to:

or any combination thereof

(b) The Second Metallocene Compound

The second metallocene compound used in accordance with the presentinvention is characterized by poorer comonomer incorporation thanInd₂ZrCl₂. Further, the second metallocene exhibits higherpolymerization activity than Ind₂ZrCl₂. The catalysts are amply, andpositively, responsive to hydrogen, affording a low molecular weightpolymer while maintaining high activity.

In accordance with the present invention, the second metallocenecompound is an unbridged metallocene compound having the formula:

wherein R² is H or —CH₃; and R³ is CH₂═CHCH₂—, CH₂═CH(CH₂)₂—, Ph(CH₂)₃—,CH₃(CH₂—)₃, or H; X⁵ and X⁶ independently are a halide; and M² is Zr orHf. In this and other aspects, (X⁵) and (X⁶) may be the same ordifferent. Examples of metallocene compounds that may be suitable foruse as the second metallocene compound in accordance with the presentinvention include, but are not limited to:

or any combination thereof.

In this and other aspects of the present invention, the ratio of thefirst metallocene compound to the second metallocene compound may befrom about 1:10 to about 10:1. In yet other aspects of the presentinvention, the ratio of the first metallocene compound to the secondmetallocene compound may be from about 1:5 to about 5:1. In still otheraspects of the present invention, the ratio of the first metallocenecompound to the second metallocene compound may be from about 1:2 toabout 2:1.

(c) Synthesis of Monocyclopentadienyl Complexes

The present invention also provides a method for preparingmonocyclopentadienyl complexes (“half-metallocene compounds”) thatresults in greater yield of the desired compound. The present inventionfurther provides a method of isolating the desired compound as a solid.While various exemplary compounds are provided herein, it should beunderstood that the method of the present invention may be used toprepare numerous other half-metallocene compounds. In one aspect, thehalf-metallocene compounds formed according to the present invention maybe used to form metallocene compounds that are suitable for use in adual catalyst system.

The presently known method of preparing a monocyclopentadienyl complexcomprises adding solid ZrCl₄ into a stirring solution of ZrCp₂Cl₂ or asubstituted Cp analogue in toluene at ambient temperature and stirringfor about 1 hour. The resulting mixture is filtered to yield the desiredproduct as a dark oil. Using this method to make such compounds, theresulting mixture consists primarily of unreacted starting materialzirconocene dichloride.

According to the present invention, the reaction mixture is refluxed intoluene for about 20 hours. By doing so, the reaction is nearlyquantitative as compared with the presently known room temperaturesynthesis.

wherein M is Zr or Hf; R² is H, an alkyl group, or an alkenyl group, andR⁴ is H, an alkyl group, or an alkenyl group. In one aspect, R² is analkyl group and R⁴ is H or an alkyl group. Thus, examples ofhalf-metallocene compounds that may be formed according to the presentinvention include, but are not limited to Zr[η-O₅H₄-(nBu)]Cl₃ andZr[η-O₅H₃-(nBu, Me)1,3]Cl₃.

According to another aspect of the present invention, the desiredhalf-metallocene compound optionally is isolated as a solid. The solidis formed by contacting the reaction mixture with CH₂Cl₂ and pentane,hexane, heptane, or any combination thereof. In one aspect, the solid isformed by contacting the reaction mixture with a mixture of CH₂Cl₂ andpentane to yield the trichlorides as a solid. The ratio of CH₂Cl₂ topentane may be 1:2, 1:3, 1:4, 1:5, or 1:6, or any other suitable ratio.Alternatively, a mixture of CH₂Cl₂ with hexane may be used.Alternatively still, a mixture of CH₂Cl₂ with heptane may be used. Theamount of CH₂Cl₂/pentane mixture used may vary for each reactionmixture, for example, for 38 g of (nBuCp)₂ZrCl₂ about 150 mL CH₂Cl₂ and300 mL of pentane may be used.

The reaction mixture may be contacted several times with theCH₂Cl₂/pentane mixture if necessary or desired. In one aspect, thereaction mixture may be contacted with the CH₂Cl₂/pentane mixture onetime. In another aspect, the reaction mixture may be contacted with theCH₂Cl₂/pentane mixture two times. In another aspect, the reactionmixture may be contacted with the CH₂Cl₂/pentane mixture three times. Inyet another aspect, the reaction mixture may be contacted with theCH₂Cl₂/pentane mixture four or more times.

This method provides the half-metallocene compound in at least about 50%yield. In one aspect, the method of the present invention provides thehalf-metallocene compound in at least about 60% yield. In anotheraspect, the method of the present invention provides thehalf-metallocene compound in at least about 70% yield. In yet anotheraspect, the method of the present invention provides thehalf-metallocene compound in at least about 80% yield. In still anotheraspect, the method of the present invention provides thehalf-metallocene compound in at least about 90% yield. In a stillfurther aspect, the method of the present invention provides thehalf-metallocene compound in at least about 95% yield.

2. The Activator-Support

The present invention encompasses various catalyst compositionsincluding an activator-support comprising a chemically-treated solidoxide. Alternatively, the activator-support may comprise a pillaredclay.

The chemically-treated solid oxide exhibits enhanced acidity as comparedto the corresponding untreated solid oxide compound. Thechemically-treated solid oxide also functions as a catalyst activator ascompared to the corresponding untreated solid oxide. While thechemically-treated solid oxide activates the metallocene in the absenceof cocatalysts, it is not necessary to eliminate cocatalysts from thecatalyst composition. The activation function of the activator-supportis evident in the enhanced activity of catalyst composition as a whole,as compared to a catalyst composition containing the correspondinguntreated solid oxide. However, it is believed that thechemically-treated solid oxide can function as an activator, even in theabsence of an organoaluminum compound, aluminoxanes, organoboroncompounds, or ionizing ionic compounds.

The chemically-treated solid oxide may comprise at least one solid oxidetreated with at least one electron-withdrawing anion. While notintending to be bound by the following statement, it is believed thattreatment of the solid oxide with an electron-withdrawing componentaugments or enhances the acidity of the oxide. Thus, theactivator-support exhibits Lewis or Brønsted acidity that is typicallygreater than the Lewis or Brønsted acid strength than the untreatedsolid oxide, or the activator-support has a greater number of acid sitesthan the untreated solid oxide, or both. One method to quantify theacidity of the chemically-treated and untreated solid oxide materials isby comparing the polymerization activities of the treated and untreatedoxides under acid catalyzed reactions.

The chemically-treated solid oxide of this invention is formed generallyfrom an inorganic solid oxide having a relatively high porosity thatexhibits Lewis acidic or Brønsted acidic behavior. The solid oxide ischemically-treated with an electron-withdrawing component, typically anelectron-withdrawing anion, to form an activator-support.

According to one aspect of the present invention, the solid oxide usedto prepare the chemically-treated solid oxide may have a pore volumegreater than about 0.1 cc/g. According to another aspect of the presentinvention, the solid oxide may have a pore volume greater than about 0.5cc/g. According to yet another aspect of the present invention, thesolid oxide may have a pore volume greater than about 1.0 cc/g.

According to another aspect of the present invention, the solid oxidemay have a surface area of from about 100 to about 1000 m²/g. Accordingto yet another aspect of the present invention, the solid oxide may havea surface area of from about 200 to about 800 m²/g. According to stillanother aspect of the present invention, the solid oxide may have asurface area of from about 250 to about 600 m²/g.

The chemically-treated solid oxide may comprise a solid inorganic oxidecomprising oxygen and at least one element selected from Group 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 of the periodic table, orcomprising oxygen and at least one element selected from the lanthanideor actinide elements. (See: Hawley's Condensed Chemical Dictionary,11^(th) Ed., John Wiley & Sons; 1995; Cotton, F. A.; Wilkinson, G.;Murillo; C. A.; and Bochmann; M. Advanced Inorganic Chemistry, 6^(th)Ed., Wiley-Interscience, 1999). For example, the inorganic oxide maycomprise oxygen and at least one element selected from Al, B, Be, Bi,Cd, Co, Cr, Cu, Fe, Ga, La, Mn, Mo, Ni, Sb, Si, Sn, Sr, Th, Ti, V, W, P,Y, Zn or Zr.

Suitable examples of solid oxide materials or compounds that can be usedto form the chemically-treated solid oxide include, but are not limitedto, Al₂O₃, B₂O₃, BeO, Bi₂O₃, CdO, Co₃O₄, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃,La₂O₃, Mn₂O₃, MoO₃, NiO, P₂O₅, Sb₂O₅, SiO₂, SnO₂, SrO, ThO₂, TiO₂, V₂O₅,WO₃, Y₂O₃, ZnO, ZrO₂, and the like, including mixed oxides thereof, andcombinations thereof. For example, the solid oxide may be silica,alumina, silica-alumina, aluminum phosphate, heteropolytungstates,titania, zirconia, magnesia, boria, zinc oxide, mixed oxides thereof, orany combination thereof.

The solid oxide of this invention encompasses oxide materials such asalumina, “mixed oxide” compounds thereof such as silica-alumina, andcombinations and mixtures thereof. The mixed oxide compounds such assilica-alumina can be single or multiple chemical phases with more thanone metal combined with oxygen to form a solid oxide compound. Examplesof mixed oxides that can be used in the activator-support of the presentinvention include, but are not limited to, silica-alumina,silica-titania, silica-zirconia, zeolites, various clay minerals,alumina-titania, alumina-zirconia, zinc-aluminate and the like.

The electron-withdrawing component used to treat the solid oxide may beany component that increases the Lewis or Brønsted acidity of the solidoxide upon treatment (as compared to the solid oxide that is not treatedwith at least one electron-withdrawing anion). According to one aspectof the present invention, the electron-withdrawing component is anelectron-withdrawing anion derived from a salt, an acid, or othercompound, such as a volatile organic compound, that may serve as asource or precursor for that anion. Examples of electron-withdrawinganions include, but are not limited to, sulfate, bisulfate, fluoride,chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, trifluoroacetate, triflate, and the like, includingmixtures and combinations thereof. In addition, other ionic or non-ioniccompounds that serve as sources for these electron-withdrawing anionsmay also be employed in the present invention.

Thus, for example, the chemically-treated solid oxide used with thepresent invention may be fluorided alumina, chlorided alumina, bromidedalumina, sulfated alumina, fluorided silica-alumina, chloridedsilica-alumina, bromided silica-alumina, sulfated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, or any combination thereof.

When the electron-withdrawing component comprises a salt of anelectron-withdrawing anion, the counterion or cation of that salt may beselected from any cation that allows the salt to revert or decomposeback to the acid during calcining. Factors that dictate the suitabilityof the particular salt to serve as a source for the electron-withdrawinganion include, but are not limited to, the solubility of the salt in thedesired solvent, the lack of adverse reactivity of the cation,ion-pairing effects between the cation and anion, hygroscopic propertiesimparted to the salt by the cation, and the like, and thermal stabilityof the anion. Examples of suitable cations in the salt of theelectron-withdrawing anion include, but are not limited to, ammonium,trialkyl ammonium, tetraalkyl ammonium, tetraalkyl phosphonium, H⁺,[H(OEt₂)₂]⁺, and the like.

Further, combinations of one or more different electron-withdrawinganions, in varying proportions, can be used to tailor the specificacidity of the activator-support to the desired level. Combinations ofelectron-withdrawing components may be contacted with the oxide materialsimultaneously or individually, and in any order that affords thedesired chemically-treated solid oxide acidity. For example, one aspectof this invention is employing two or more electron-withdrawing anionsource compounds in two or more separate contacting steps.

Thus, one example of such a process by which an chemically-treated solidoxide is prepared is as follows: a selected solid oxide compound, orcombination of oxide compounds, is contacted with a firstelectron-withdrawing anion source compound to form a first mixture; thisfirst mixture is calcined and then contacted with a secondelectron-withdrawing anion source compound to form a second mixture; thesecond mixture is then calcined to form a treated solid oxide compound.In such a process, the first and second electron-withdrawing anionsource compounds may be different compounds or the same compound.

According to another aspect of the present invention, thechemically-treated solid oxide may comprise a solid inorganic oxidematerial, a mixed oxide material, or a combination of inorganic oxidematerials, that is chemically-treated with an electron-withdrawingcomponent, and optionally treated with a metal source, including metalsalts, metal ions, or other metal-containing compounds. The metal ormetal ion may be, for example, zinc, nickel, vanadium, titanium, silver,copper, gallium, tin, tungsten, molybdenum, or any combination thereof.Examples of chemically-treated solid oxides that include a metal ormetal ion include, but are not limited to, zinc-impregnated chloridedalumina, titanium-impregnated fluorided alumina, zinc-impregnatedfluorided alumina, zinc-impregnated chlorided silica-alumina,zinc-impregnated fluorided silica-alumina, zinc-impregnated sulfatedalumina, chlorided zinc aluminate, fluorided zinc aluminate, sulfatedzinc aluminate, or any combination thereof.

Any method of impregnating the solid oxide material with a metal may beused. The method by which the oxide is contacted with a metal source,typically a salt or metal-containing compound, may include, but is notlimited to, gelling, co-gelling, impregnation of one compound ontoanother, and the like. If desired, the metal-containing compound may beadded to or impregnated into the solid oxide in solution form, andsubsequently converted into the supported metal upon calcining.Accordingly, the solid inorganic oxide can further comprise a metalselected from zinc, titanium, nickel, vanadium, silver, copper, gallium,tin, tungsten, molybdenum, or a combination thereof. For example, zincmay be used to impregnate the solid oxide because it provides goodcatalyst activity and low cost.

The solid oxide may be treated with metal salts or metal-containingcompounds before, after, or at the same time that the solid oxide istreated with the electron-withdrawing anion. Following any contactingmethod, the contacted mixture of oxide compound, electron-withdrawinganion, and the metal ion is typically calcined. Alternatively, a solidoxide material, an electron-withdrawing anion source, and the metal saltor metal-containing compound are contacted and calcined simultaneously.

Various processes may be used to form the chemically-treated solidoxide. The chemically-treated solid oxide may comprise the contactproduct of at least one solid oxide compound and at least oneelectron-withdrawing anion source. It is not required that the solidoxide compound be calcined prior to contacting the electron-withdrawinganion source. The contact product may be calcined either during or afterthe solid oxide compound is contacted with the electron-withdrawinganion source. The solid oxide compound may be calcined or uncalcined.Various processes to prepare solid oxide activator-supports that can beemployed in this invention have been reported. For example, such methodsare described in U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494,6,300,271, 6,316,553, 6,355,594, 6,376,415, 6,391,816, 6,395,666,6,524,987, and 6,548,441, each of which is incorporated by referenceherein in its entirety.

According to one aspect of the present invention, the solid oxidematerial may be chemically-treated by contacting it with at least oneelectron-withdrawing component, typically an electron-withdrawing anionsource. Further, the solid oxide material optionally may be chemicallytreated with a metal ion, and then calcined to form a metal-containingor metal-impregnated chemically-treated solid oxide. According toanother aspect of the present invention, the solid oxide material andelectron-withdrawing anion source are contacted and calcinedsimultaneously. The method by which the oxide is contacted with theelectron-withdrawing component, typically a salt or an acid of anelectron-withdrawing anion, may include, but is not limited to, gelling,co-gelling, impregnation of one compound onto another, and the like.Thus, following any contacting method, the contacted mixture of thesolid oxide, electron-withdrawing anion, and optional metal ion, iscalcined.

The solid oxide activator-support (chemically-treated solid oxide) maythus be produced by a process comprising:

1) contacting a solid oxide compound with at least oneelectron-withdrawing anion source compound to form a first mixture; and

2) calcining the first mixture to form the solid oxideactivator-support.

According to another aspect of the present invention, the solid oxideactivator-support (chemically-treated solid oxide) may be produced by aprocess comprising:

1) contacting at least one solid oxide compound with a firstelectron-withdrawing anion source compound to form a first mixture;

2) calcining the first mixture to produce a calcined first mixture;

3) contacting the calcined first mixture with a secondelectron-withdrawing anion source compound to form a second mixture; and

4) calcining the second mixture to form the solid oxideactivator-support.

According to yet another aspect of the present invention, thechemically-treated solid oxide is produced or formed by contacting thesolid oxide with the electron-withdrawing anion source compound, wherethe solid oxide compound is calcined before, during, or after contactingthe electron-withdrawing anion source, and where there is a substantialabsence of aluminoxanes and organoborates.

Calcining of the treated solid oxide generally is conducted in anambient atmosphere, typically in a dry ambient atmosphere, at atemperature from about 200° C. to about 900° C., for about 1 minute toabout 100 hours. Calcining may be conducted at a temperature of fromabout 300° C. to about 800° C., for example, at a temperature of fromabout 400° C. to about 700° C. Calcining may be conducted for about 1hour to about 50 hours, for example, for about 3 hours to about 20hours. Thus, for example, calcining may be carried out for about 1 toabout 10 hours at a temperature of from about 350° C. to about 550° C.Any type of suitable ambient can be used during calcining. Generally,calcining is conducted in an oxidizing atmosphere, such as air.Alternatively, an inert atmosphere, such as nitrogen or argon, or areducing atmosphere, such as hydrogen or carbon monoxide, may be used.

According to one aspect of the present invention, the solid oxidematerial may be treated with a source of halide ion, sulfate ion, or acombination of anions, optionally treated with a metal ion, and thencalcined to provide the chemically-treated solid oxide in the form of aparticulate solid. For example, the solid oxide material may be treatedwith a source of sulfate (termed a “sulfating agent”), a source ofchloride ion (termed a “chloriding agent”), a source of fluoride ion(termed a “fluoriding agent”), or a combination thereof, and calcined toprovide the solid oxide activator. Useful acidic activator-supportsinclude, but are not limited to, bromided alumina, chlorided alumina,fluorided alumina, sulfated alumina, bromided silica-alumina, chloridedsilica-alumina, fluorided silica-alumina, sulfated silica-alumina,bromided silica-zirconia, chlorided silica-zirconia, fluoridedsilica-zirconia, sulfated silica-zirconia; a pillared clay, such as apillared montmorillonite, optionally treated with fluoride, chloride, orsulfate; phosphated alumina or other aluminophosphates optionallytreated with sulfate, fluoride, or chloride; or any combination of theabove. Further, any of the activator-supports optionally may be treatedwith a metal ion.

The chemically-treated solid oxide may comprise a fluorided solid oxidein the form of a particulate solid. The fluorided solid oxide may beformed by contacting a solid oxide with a fluoriding agent. The fluorideion may be added to the oxide by forming a slurry of the oxide in asuitable solvent such as alcohol or water including, but are not limitedto, the one to three carbon alcohols because of their volatility and lowsurface tension. Examples of fluoriding agents that may be suitableinclude, but are not limited to, hydrofluoric acid (HF), ammoniumfluoride (NH₄F), ammonium bifluoride (NH₄HF₂), ammoniumtetrafluoroborate (NH₄BF₄), ammonium silicofluoride (hexafluorosilicate)((NH₄)₂SiF₆), ammonium hexafluorophosphate (NH₄PF₆), analogs thereof,and combinations thereof. For example, ammonium bifluoride NH₄HF₂ may beused as the fluoriding agent, due to its ease of use and readyavailability.

If desired, the solid oxide may be treated with a fluoriding agentduring the calcining step. Any fluoriding agent capable of thoroughlycontacting the solid oxide during the calcining step can be used. Forexample, in addition to those fluoriding agents described previously,volatile organic fluoriding agents may be used. Examples of volatileorganic fluoriding agents useful in this aspect of the inventioninclude, but are not limited to, freons, perfluorohexane,perfluorobenzene, fluoromethane, trifluoroethanol, and combinationsthereof. Gaseous hydrogen fluoride or fluorine itself also can be usedwith the solid oxide is fluorided during calcining. One convenientmethod of contacting the solid oxide with the fluoriding agent is tovaporize a fluoriding agent into a gas stream used to fluidize the solidoxide during calcination.

Similarly, in another aspect of this invention, the chemically-treatedsolid oxide may comprise a chlorided solid oxide in the form of aparticulate solid. The chlorided solid oxide may be formed by contactinga solid oxide with a chloriding agent. The chloride ion may be added tothe oxide by forming a slurry of the oxide in a suitable solvent. Thesolid oxide may be treated with a chloriding agent during the calciningstep. Any chloriding agent capable of serving as a source of chlorideand thoroughly contacting the oxide during the calcining step may beused. For example, volatile organic chloriding agents may be used.Examples of volatile organic chloriding agents that may be suitableinclude, but are not limited to, certain freons, perchlorobenzene,chloromethane, dichloromethane, chloroform, carbon tetrachloride,trichloroethanol, or any combination thereof. Gaseous hydrogen chlorideor chlorine itself may also be used with the solid oxide duringcalcining. One convenient method of contacting the oxide with thechloriding agent is to vaporize a chloriding agent into a gas streamused to fluidize the solid oxide during calcination.

The amount of fluoride or chloride ion present before calcining thesolid oxide may be from about 2 to about 50% by weight, where weightpercent is based on the weight of the solid oxide, for example,silica-alumina, before calcining. According to another aspect of thisinvention, the amount of fluoride or chloride ion present beforecalcining the solid oxide may be from about 3 to about 25% by weight,and according to another aspect of this invention, may be from about 4to about 20% by weight. Once impregnated with halide, the halided oxidemay be dried by any method known in the art including, but not limitedto, suction filtration followed by evaporation, drying under vacuum,spray drying, and the like, although it is also possible to initiate thecalcining step immediately without drying the impregnated solid oxide.

The silica-alumina used to prepare the treated silica-alumina typicallyhas a pore volume greater than about 0.5 cc/g. According to one aspectof the present invention, the pore volume may be greater than about 0.8cc/g, and according to another aspect of the present invention, the porevolume may be greater than about 1.0 cc/g. Further, the silica-aluminamay have a surface area greater than about 100 m²/g. According to oneaspect of this invention, the surface area may be greater than about 250m²/g, and according to another aspect of this invention, the surfacearea may be greater than about 350 m²/g.

The silica-alumina used with the present invention typically has analumina content from about 5 to about 95%. According to one aspect ofthis invention, the alumina content of the silica-alumina may be fromabout 5 to about 50%, and according to another aspect of this invention,the alumina content of the silica-alumina may be from about 8% to about30% alumina by weight. According to yet another aspect of thisinvention, the solid oxide component may comprise alumina withoutsilica, and according to another aspect of this invention, the solidoxide component may comprise silica without alumina.

The sulfated solid oxide comprises sulfate and a solid oxide component,such as alumina or silica-alumina, in the form of a particulate solid.Optionally, the sulfated oxide may be treated further with a metal ionsuch that the calcined sulfated oxide comprises a metal. According toone aspect of the present invention, the sulfated solid oxide comprisessulfate and alumina. In some instances, the sulfated alumina is formedby a process wherein the alumina is treated with a sulfate source, forexample, but not limited to, sulfuric acid or a sulfate salt such asammonium sulfate. This process may be performed by forming a slurry ofthe alumina in a suitable solvent, such as alcohol or water, in whichthe desired concentration of the sulfating agent has been added.Suitable organic solvents include, but are not limited to, the one tothree carbon alcohols because of their volatility and low surfacetension.

According to one aspect of this invention, the amount of sulfate ionpresent before calcining may be from about 0.5 parts by weight to about100 parts by weight sulfate ion to about 100 parts by weight solidoxide. According to another aspect of this invention, the amount ofsulfate ion present before calcining may be from about 1 part by weightto about 50 parts by weight sulfate ion to about 100 parts by weightsolid oxide, and according to still another aspect of this invention,from about 5 parts by weight to about 30 parts by weight sulfate ion toabout 100 parts by weight solid oxide. These weight ratios are based onthe weight of the solid oxide before calcining Once impregnated withsulfate, the sulfated oxide may be dried by any method known in the artincluding, but not limited to, suction filtration followed byevaporation, drying under vacuum, spray drying, and the like, althoughit is also possible to initiate the calcining step immediately.

According to another aspect of the present invention, activator-supportcomprises a pillared clay. The term “pillared clay” is used to refer toclay materials that have been ion exchanged with large, typicallypolynuclear, highly charged metal complex cations. Examples of such ionsinclude, but are not limited to, Keggin ions which can have charges suchas 7+, various polyoxometallates, and other large ions. Thus, the termpillaring refers to a simple exchange reaction in which the exchangeablecations of a clay material are replaced with large, highly charged ions,such as Keggin ions. These polymeric cations are then immobilized withinthe interlayers of the clay and when calcined are converted to metaloxide “pillars”, effectively supporting the clay layers as column-likestructures. Thus, once the clay is dried and calcined to produce thesupporting pillars between clay layers, the expanded lattice structureis maintained and the porosity is enhanced. The resulting pores can varyin shape and size as a function of the pillaring material and the parentclay material used. Examples of pillaring and pillared clays are foundin: T. J. Pinnavaia, Science 220 (4595), 365-371 (1983); J. M. Thomas,Intercalation Chemistry, (S. Whittington and A. Jacobson, eds.) Ch. 3,pp. 55-99, Academic Press, Inc., (1972); U.S. Pat. No. 4,452,910; U.S.Pat. No. 5,376,611; and U.S. Pat. No. 4,060,480; each of which isincorporated herein in its entirety.

The pillaring process utilizes clay minerals having exchangeable cationsand layers capable of expanding. Any pillared clay that can enhance thepolymerization of olefins in the catalyst composition of the presentinvention may be used. Therefore, suitable clay minerals for pillaringinclude, but are not limited to: allophanes; smectites, bothdioctahedral (Al) and tri-octahedral (Mg) and derivatives thereof suchas montmorillonites (bentonites), nontronites, hectorites, or laponites;halloysites; vermiculites; micas; fluoromicas; chlorites; mixed-layerclays; the fiberous clays including but not limited to sepiolites,attapulgites, and palygorskites; a serpentine clay; illite; laponite;saponite; and any combination thereof. In one aspect, the pillared clayactivator-support comprises bentonite or montmorillonite. The principalcomponent of bentonite is montmorillonite.

The pillared clay may be pretreated if desired. For example, a pillaredbentonite may be pretreated by drying at about 300° C. under an inertatmosphere, typically dry nitrogen, for about 3 hours, before beingadded to the polymerization reactor. Although an exemplary pretreatmentis described herein, it should be understood that the preheating can becarried out at many other temperatures and times, including anycombination of temperature and time steps, all of which are encompassedby this invention.

The activator-support used to prepare the catalyst compositions of thepresent invention may be combined with other inorganic supportmaterials, including, but are not limited to, zeolites, inorganicoxides, phosphated inorganic oxides, and the like. In one aspect,typical support materials that may be used include, but are not limitedto, silica, silica-alumina, alumina, titania, zirconia, magnesia, boria,fluorided alumina, silated alumina, thoria, aluminophosphate, aluminumphosphate, phosphated silica, phosphated alumina, silica-titania,coprecipitated silica/titania, fluorided/silated alumina, and anycombination or mixture thereof.

According to yet another aspect of the present invention, one or more ofthe metallocene compounds may be precontacted with an olefin monomer andan organoaluminum compound for a first period of time prior tocontacting this mixture with the activator-support. Once theprecontacted mixture of the metallocene compound(s), olefin monomer, andorganoaluminum compound is contacted with the activator-support, thecomposition further comprising the activator-support is termed the“postcontacted” mixture. The postcontacted mixture may be allowed toremain in further contact for a second period of time prior to beingcharged into the reactor in which the polymerization process will becarried out.

3. The Organoaluminum Compound

Organoaluminum compounds that may be used with the present inventioninclude, but are not limited to, compounds having the formula:

(R²)₃Al;

where (R²) is an aliphatic group having from 2 to about 6 carbon atoms.For example, (R²) may be an ethyl group, a propyl group, a butyl group,a hexyl group, or an isobutyl group.

Other organoaluminum compounds that may be used in accordance with thepresent invention include, but are not limited to, compounds having theformula:

Al(X⁹)_(n)(X¹⁰)_(3-n),

where (X⁹) is a hydrocarbyl having from 1 to about 20 carbon atoms,(X¹⁰) is an alkoxide or an aryloxide, any one of which having from 1 toabout 20 carbon atoms, a halide, or a hydride, and n is a number from 1to 3, inclusive. According to one aspect of the present invention, (X⁹)is an alkyl having from 1 to about 10 carbon atoms. Examples of (X⁹)moieties include, but are not limited to, ethyl, propyl, n-butyl,sec-butyl, isobutyl, hexyl, and the like. According to another aspect ofthe present invention, (X¹⁰) may be independently selected from fluoroor chloro. According to yet another aspect of the present invention,(X¹⁰) may be chloro. In the formula Al(X⁹)_(n)(X¹⁰)_(3-n), is a numberfrom 1 to 3 inclusive, and typically, n is 3. The value of n is notrestricted to be an integer; therefore, this formula includessesquihalide compounds or other organoaluminum cluster compounds.

Examples of organoaluminum compounds that may be suitable for use withthe present invention include, but are not limited to, trialkylaluminumcompounds, dialkylaluminium halide compounds, dialkylaluminum alkoxidecompounds, dialkylaluminum hydride compounds, and combinations thereof.Specific examples of organoaluminum compounds that may be suitableinclude, but are not limited to: trimethylaluminum (TMA),triethylaluminum (TEA), tripropylaluminum, diethylaluminum ethoxide,tributylaluminum, disobutylaluminum hydride, triisobutylaluminum (TIBA),and diethylaluminum chloride.

The present invention contemplates precontacting the first metallocenecompound, the second metallocene compound, or both, with at least oneorganoaluminum compound and an olefin monomer to form a precontactedmixture, prior to contacting this precontacted mixture with theactivator-support to form the active catalyst. When the catalystcomposition is prepared in this manner, typically, though notnecessarily, a portion of the organoaluminum compound is added to theprecontacted mixture and another portion of the organoaluminum compoundis added to the postcontacted mixture prepared when the precontactedmixture is contacted with the solid oxide activator. However, the entireorganoaluminum compound may be used to prepare the catalyst in eitherthe precontacting or postcontacting step. Alternatively, all thecatalyst components may be contacted in a single step.

Further, more than one organoaluminum compound may be used in either theprecontacting or the postcontacting step. When an organoaluminumcompound is added in multiple steps, the amounts of organoaluminumcompound disclosed herein include the total amount of organoaluminumcompound used in both the precontacted and postcontacted mixtures, andany additional organoaluminum compound added to the polymerizationreactor. Therefore, total amounts of organoaluminum compounds aredisclosed regardless of whether a single organoaluminum compound or morethan one organoaluminum compound is used.

4. The Optional Aluminoxane Cocatalyst

The present invention further provides a catalyst composition comprisingan optional aluminoxane cocatalyst. As used herein. the term“aluminoxane” refers to aluminoxane compounds, compositions, mixtures,or discrete species, regardless of how such aluminoxanes are prepared,formed or otherwise provided. For example, a catalyst compositioncomprising an optional aluminoxane cocatalyst can be prepared in whichaluminoxane is provided as the poly(hydrocarbyl aluminum oxide), or inwhich aluminoxane is provided as the combination of an aluminum alkylcompound and a source of active protons such as water. Aluminoxanes arealso referred to as poly(hydrocarbyl aluminum oxides) ororganoaluminoxanes.

The other catalyst components typically are contacted with thealuminoxane in a saturated hydrocarbon compound solvent, though anysolvent that is substantially inert to the reactants, intermediates, andproducts of the activation step may be used. The catalyst compositionformed in this manner may be collected by methods known to those ofskill in the art including, but not limited to, filtration.Alternatively, the catalyst composition may be introduced into thepolymerization reactor without being isolated.

The aluminoxane compound of this invention may be an oligomeric aluminumcompound comprising linear structures, cyclic, or cage structures, ormixtures of all three. Cyclic aluminoxane compounds having the formula:

wherein R is a linear or branched alkyl having from 1 to 10 carbonatoms, and n is an integer from 3 to about 10, are encompassed by thisinvention. The (AlRO)_(n) moiety shown here also constitutes therepeating unit in a linear aluminoxane. Thus, linear aluminoxanes havingthe formula:

wherein R is a linear or branched alkyl having from 1 to 10 carbonatoms, and n is an integer from 1 to about 50, are also encompassed bythis invention.

Further, aluminoxanes may also have cage structures of the formula R^(t)_(5m+α)R^(b) _(m−α)Al_(4m)O_(3m), wherein m is 3 or 4 and α is=n_(Al(3))−n_(O(2))+n_(O(4)), wherein n_(Al(3)) is the number of threecoordinate aluminum atoms, n_(O(2)) is the number of two coordinateoxygen atoms, n_(O(4)) is the number of 4 coordinate oxygen atoms, R^(t)is a terminal alkyl group, and R^(b) is a bridging alkyl group, and R isa linear or branched alkyl having from 1 to 10 carbon atoms.

Thus, aluminoxanes that may serve as optional cocatalysts in thisinvention are represented generally by formulas such as (R—Al—O)_(n),R(R—Al—O)_(n)AlR₂, and the like, wherein the R group is typically alinear or branched C₁-C₆ alkyl such as methyl, ethyl, propyl, butyl,pentyl, or hexyl, and n typically represents an integer from 1 to about50. Examples of aluminoxane compounds that may be used in accordancewith the present invention include, but are not limited to,methylaluminoxane, ethylaluminoxane, n-propylaluminoxane,iso-propyl-aluminoxane, n-butylaluminoxane, t-butylaluminoxane,sec-butylaluminoxane, iso-butylaluminoxane, 1-pentylaluminoxane,2-pentylaluminoxane, 3-pentyl-aluminoxane, iso-pentylaluminoxane,neopentylaluminoxane, or any combination thereof. Methyl aluminoxane,ethyl aluminoxane, and isobutyl aluminoxane are prepared fromtrimethylaluminum, triethylaluminum, or triisobutylaluminum,respectively, and sometimes are referred to as poly(methyl aluminumoxide), poly(ethyl aluminum oxide), and poly(isobutyl aluminum oxide),respectively. It is also within the scope of the invention to use analuminoxane in combination with a trialkylaluminum, such as thatdisclosed in U.S. Pat. No. 4,794,096, incorporated herein by referencein its entirety.

The present invention contemplates many values of n in the aluminoxaneformulas (R—Al—O)_(n) and R(R—Al—O)_(n)AlR₂, and n typically may be atleast about 3. However, depending upon how the organoaluminoxane isprepared, stored, and used, the value of n may vary within a singlesample of aluminoxane, and such combinations of organoaluminoxanes arecontemplated hereby.

In preparing the catalyst composition of this invention comprising anoptional aluminoxane, the molar ratio of the aluminum in the aluminoxaneto the metallocene in the composition may be from about 1:10 to about100,000:1, for example, from about 5:1 to about 15,000:1. The amount ofoptional aluminoxane added to a polymerization zone may be from about0.01 mg/L to about 1000 mg/L, from about 0.1 mg/L to about 100 mg/L, orfrom about 1 mg/L to about 50 mg/L.

Organoaluminoxanes may be prepared by various procedures that are wellknown in the art. Examples of organoaluminoxane preparations aredisclosed in U.S. Pat. Nos. 3,242,099 and 4,808,561, each of which isincorporated by reference herein in its entirety. For example, water inan inert organic solvent may be reacted with an aluminum alkyl compoundsuch as AlR₃ to form the desired organoaluminoxane compound. While notintending to be bound by this statement, it is believed that thissynthetic method can afford a mixture of both linear and cyclic(R—Al—O)_(n) aluminoxane species, both of which are encompassed by thisinvention. Alternatively, organoaluminoxanes may be prepared by reactingan aluminum alkyl compound, such as AlR₃ with a hydrated salt, such ashydrated copper sulfate, in an inert organic solvent.

5. The Optional Organoboron Cocatalyst

The present invention further provides a catalyst composition comprisingan optional organoboron cocatalyst. The organoboron compound maycomprise neutral boron compounds, borate salts, or any combinationthereof. For example, the organoboron compounds of this invention maycomprise a fluoroorgano boron compound, a fluoroorgano borate compound,or a combination thereof.

Any fluoroorgano boron or fluoroorgano borate compound known in the artcan be utilized with the present invention. Examples of fluoroorganoborate compounds that may be used as cocatalysts in the presentinvention include, but are not limited to, fluorinated aryl borates suchas N,N-dimethylanilinium tetrakis-(pentafluorophenyl)borate,triphenylcarbenium tetrakis(pentafluorophenyl)borate, lithiumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, triphenylcarbeniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and the like, includingmixtures thereof. Examples of fluoroorgano boron compounds that can beused as cocatalysts in the present invention include, but are notlimited to, tris(pentafluorophenyl)boron,tris[3,5-bis(trifluoromethyl)phenyl]boron, and the like, includingmixtures thereof. Although not intending to be bound by the followingtheory, these examples of fluoroorgano borate and fluoroorgano boroncompounds, and related compounds, are thought to form“weakly-coordinating” anions when combined with organometal compounds,as disclosed in U.S. Pat. No. 5,919,983, incorporated herein byreference in its entirety.

Generally, any amount of organoboron compound may be used. According toone aspect of this invention, the molar ratio of the organoboroncompound to the metallocene compound in the composition may be fromabout 0.1:1 to about 10:1. Typically, the amount of the fluoroorganoboron or fluoroorgano borate compound used as a cocatalyst for themetallocenes may be from about 0.5 mole to about 10 moles of boroncompound per total moles of the metallocene compounds. According toanother aspect of this invention, the amount of fluoroorgano boron orfluoroorgano borate compound may be from about 0.8 mole to about 5 molesof boron compound per total moles of the metallocene compound.

6. The Optional Ionizing Ionic Compound Cocatalyst

The present invention further provides a catalyst composition comprisingan optional ionizing ionic compound cocatalyst. An ionizing ioniccompound is an ionic compound that can function to enhance the activityof the catalyst composition. While not intending to be bound by theory,it is believed that the ionizing ionic compound may be capable ofreacting with a metallocene compound and converting the metallocene intoone or more cationic metallocene compounds, or incipient cationicmetallocene compounds. Again, while not intending to be bound by theory,it is believed that the ionizing ionic compound may function as anionizing compound by completely or partially extracting an anionicligand, possibly a non-η⁵-alkadienyl ligand such as (X³) or (X⁴), fromthe metallocene. However, the ionizing ionic compound is an activatorregardless of whether it is ionizes the metallocene, abstracts an (X³)or (X⁴) ligand in a fashion as to form an ion pair, weakens themetal-(X³) or metal-(X⁴) bond in the metallocene, simply coordinates toan (X³) or (X⁴) ligand, or activates the metallocene by some othermechanism.

Further, it is not necessary that the ionizing ionic compound activatethe metallocenes only. The activation function of the ionizing ioniccompound is evident in the enhanced activity of catalyst composition asa whole, as compared to a catalyst composition containing catalystcomposition that does not comprise any ionizing ionic compound. It isalso not necessary that the ionizing ionic compound activate each of themetallocene compounds present, nor is it necessary that it activate theany of the metallocene compounds to the same extent.

Examples of ionizing ionic compounds include, but are not limited to,the following compounds: tri(n-butyl)ammonium tetrakis(p-tolyl)borate,tri(n-butyl)-ammonium tetrakis(m-tolyl)borate, tri(n-butyl)ammoniumtetrakis(2,4-dimethyl)-borate, tri(n-butyl)ammoniumtetrakis(3,5-dimethylphenyl)borate, tri(n-butyl)-ammoniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, tri(n-butyl)ammoniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(p-tolyl)borate, N,N-dimethylanilinium tetrakis(m-tolyl)borate,N,N-dimethylanilinium tetrakis(2,4-dimethylphenyl)_(b) orate,N,N-dimethylanilinium tetrakis(3,5-dimethylphenyl)borate,N,N-dimethylanilinium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate,N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,triphenylcarbenium tetrakis(p-tolyl)borate, triphenylcarbeniumtetrakis(m-tolyl)borate, triphenylcarbeniumtetrakis(2,4-dimethylphenyl)borate, triphenylcarbeniumtetrakis(3,5-dimethylphenyl)borate, triphenylcarbeniumtetrakis[3,5-bis(trifluoro-methyl)phenyl]borate, triphenylcarbeniumtetrakis(pentafluorophenyl)borate, tropylium tetrakis(p-tolyl)borate,tropylium tetrakis(m-tolyl)borate, tropyliumtetrakis(2,4-dimethylphenyl)borate, tropyliumtetrakis(3,5-dimethylphenyl)borate, tropyliumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, tropyliumtetrakis(pentafluorophenyl)borate, lithiumtetrakis(pentafluorophenyl)borate, lithium tetrakis(phenyl)borate,lithium tetrakis(p-tolyl)borate, lithium tetrakis(m-tolyl)borate,lithium tetrakis(2,4-dimethylphenyl)borate, lithiumtetrakis(3,5-dimethylphenyl)borate, lithium tetrafluoroborate, sodiumtetrakis(pentafluoro-phenyl)borate, sodium tetrakis(phenyl) borate,sodium tetrakis(p-tolyl)borate, sodium tetrakis(m-tolyl)borate, sodiumtetrakis(2,4-dimethylphenyl)borate, sodiumtetrakis(3,5-dimethylphenyl)borate, sodium tetrafluoroborate, potassiumtetrakis-(pentafluorophenyl)borate, potassium tetrakis(phenyl)borate,potassium tetrakis(p-tolyl)borate, potassium tetrakis(m-tolyl)borate,potassium tetrakis(2,4-dimethyl-phenyl)borate, potassiumtetrakis(3,5-dimethylphenyl)borate, potassium tetrafluoro-borate,tri(n-butyl)ammonium tetrakis(p-tolyl)aluminate, tri(n-butyl)ammoniumtetrakis(m-tolyl)aluminate, tri(n-butyl)ammoniumtetrakis(2,4-dimethyl)aluminate, tri(n-butyl)ammoniumtetrakis(3,5-dimethylphenyl)aluminate, tri(n-butyl)ammoniumtetrakis(pentafluorophenyl)aluminate, N,N-dimethylaniliniumtetrakis(p-tolyl)aluminate, N,N-dimethylaniliniumtetrakis(m-tolyl)aluminate, N,N-dimethylaniliniumtetrakis(2,4-dimethylphenyl)aluminate, N,N-dimethylaniliniumtetrakis(3,5-dimethylphenyl)aluminate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)aluminate, triphenylcarbeniumtetrakis(p-tolyl)aluminate, triphenylcarbeniumtetrakis(m-tolyl)aluminate, triphenylcarbeniumtetrakis(2,4-dimethylphenyl)aluminate, triphenylcarbeniumtetrakis(3,5-dimethylphenyl)aluminate, triphenylcarbeniumtetrakis-(pentafluorophenyl)aluminate, tropyliumtetrakis(p-tolyl)aluminate, tropylium tetrakis(m-tolyl)aluminate,tropylium tetrakis(2,4-dimethylphenyl)aluminate, tropyliumtetrakis(3,5-dimethylphenyl)aluminate, tropyliumtetrakis(pentafluoro-phenyl)aluminate, lithiumtetrakis(pentafluorophenyl)aluminate, lithiumtetrakis-(phenyl)aluminate, lithium tetrakis(p-tolyl)aluminate, lithiumtetrakis(m-tolyl)aluminate, lithiumtetrakis(2,4-dimethylphenyl)aluminate, lithiumtetrakis(3,5-dimethylphenyl)aluminate, lithium tetrafluoroaluminate,sodium tetrakis(pentafluorophenyl)aluminate, sodiumtetrakis(phenyl)aluminate, sodium tetrakis(p-tolyl)aluminate, sodiumtetrakis(m-tolyl)aluminate, sodiumtetrakis(2,4-dimethylphenyl)aluminate, sodiumtetrakis(3,5-dimethylphenyl)aluminate, sodium tetrafluoroaluminate,potassium tetrakis(pentafluorophenyl)aluminate, potassiumtetrakis(phenyl)aluminate, potassium tetrakis(p-tolyl)aluminate,potassium tetrakis(m-tolyl)aluminate, potassiumtetrakis(2,4-dimethylphenyl)aluminate, potassiumtetrakis(3,5-dimethylphenyl)aluminate, potassium tetrafluoroaluminate,and the like. However, the optional ionizing ionic compounds that areuseful in this invention are not limited to these. Other examples ofionizing ionic compounds are disclosed in U.S. Pat. Nos. 5,576,259 and5,807,938, each of which is incorporated herein by reference in itsentirety.

B. Olefin Monomer

Unsaturated reactants that may be useful with catalyst compositions andpolymerization processes of this invention include olefin compoundshaving from about 2 to about 30 carbon atoms per molecule and at leastone olefinic double bond. This invention encompasses homopolymerizationprocesses using a single olefin such as ethylene or propylene, as wellas copolymerization reactions with at least one different olefiniccompound. The resulting copolymer may comprise a major amount ofethylene (>50 mole percent) and a minor amount of comonomer <50 molepercent), though this is not a requirement. The comonomers that may becopolymerized with ethylene typically may have from three to about 20carbon atoms in their molecular chain.

Acyclic, cyclic, polycyclic, terminal (α), internal, linear, branched,substituted, unsubstituted, functionalized, and non-functionalizedolefins may be employed in this invention. For example, typicalunsaturated compounds that may be polymerized with the catalysts of thisinvention include, but are not limited to, propylene, 1-butene,2-butene, 3-methyl-1-butene, isobutylene, 1-pentene, 2-pentene,3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 2-hexene, 3-hexene,3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, the four normaloctenes, the four normal nonenes, the five normal decenes, and mixturesof any two or more thereof. Cyclic and bicyclic olefins, including butnot limited to, cyclopentene, cyclohexene, norbornylene, norbornadiene,and the like, may also be polymerized as described above.

When a copolymer is desired, the monomer ethylene may be copolymerizedwith a comonomer. Examples of the comonomer include, but are not limitedto, propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene,1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,2-hexene, 3-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene,the four normal octenes, the four normal nonenes, or the five normaldecenes. According to one aspect of the present invention, the comonomermay be selected from 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene,or styrene.

The amount of comonomer introduced into a reactor zone to produce thecopolymer generally may be from about 0.01 to about 50 weight percentcomonomer based on the total weight of the monomer and comonomer.According to another aspect of the present invention, the amount ofcomonomer introduced into a reactor zone may be from about 0.01 to about40 weight percent comonomer based on the total weight of the monomer andcomonomer. According to still another aspect of the present invention,the amount of comonomer introduced into a reactor zone may be from about0.1 to about 35 weight percent comonomer based on the total weight ofthe monomer and comonomer. Alternatively, the amount of comonomerintroduced into a reactor zone may be any amount sufficient to providethe above concentrations by weight.

While not intending to be bound by this theory, where branched,substituted, or functionalized olefins are used as reactants, it isbelieved that steric hindrance may impede and/or slow the polymerizationprocess. Thus, branched and/or cyclic portion(s) of the olefin removedsomewhat from the carbon-carbon double bond would not be expected tohinder the reaction in the way that the same olefin substituentssituated more proximate to the carbon-carbon double bond might.According to one aspect of the present invention, at least one reactantfor the catalyst compositions of this invention may be ethylene, so thepolymerizations are either homopolymerizations or copolymerizations witha different acyclic, cyclic, terminal, internal, linear, branched,substituted, or unsubstituted olefin. In addition, the catalystcompositions of this invention may be used in the polymerization ofdiolefin compounds including, but not limited to, 1,3-butadiene,isoprene, 1,4-pentadiene, and 1,5-hexadiene.

C. Preparation of the Catalyst Composition

The present invention encompasses a catalyst composition comprising thecontact product of a first metallocene compound, a second metallocenecompound, an activator-support, and an organoaluminum compound. Thisinvention further encompasses methods of making the catalyst compositionencompassing contacting a first metallocene compound, a secondmetallocene compound, an activator-support, and an organoaluminumcompound, in any order. According to such methods, an active catalystcomposition is obtained when the catalyst components are contacted inany sequence or order.

One or more of the metallocene compounds may be precontacted with anolefinic monomer if desired, not necessarily the olefin monomer to bepolymerized, and an organoaluminum cocatalyst for a first period of timeprior to contacting this precontacted mixture with theactivator-support. The first period of time for contact, the precontacttime, between the metallocene compound or compounds, the olefinicmonomer, and the organoaluminum compound typically may range from timeabout 0.1 hour to about 24 hours, for example, from about 0.1 to about 1hour. Precontact times from about 10 minutes to about 30 minutes arealso typical.

Once the precontacted mixture of the metallocene compound or compounds,olefin monomer, and organoaluminum cocatalyst is contacted with theactivator-support, this composition (further comprising theactivator-support) is termed the “postcontacted mixture”. Thepostcontacted mixture optionally may be allowed to remain in contact fora second period of time, the postcontact time, prior to initiating thepolymerization process. Postcontact times between the precontactedmixture and the activator-support may range in time from about 0.1 hourto about 24 hours, for example, from about 0.1 hour to about 1 hour. Theprecontacting, the postcontacting step, or both may increase theproductivity of the polymer as compared to the same catalyst compositionthat is prepared without precontacting or postcontacting. However,neither a precontacting step nor a postcontacting step is required.

The postcontacted mixture may be heated at a temperature and for aduration sufficient to allow adsorption, impregnation, or interaction ofprecontacted mixture and the activator-support, such that a portion ofthe components of the precontacted mixture is immobilized, adsorbed, ordeposited thereon. Where heating is used, the postcontacted mixture maybe heated from between about 0° F. to about 150° F., for example, fromabout 40° F. to about 95° F.

According to one aspect of this invention, the molar ratio of the totalmoles of the metallocene compounds to the organoaluminum compound may befrom about 1:1 to about 1:10,000. According to another aspect of thisinvention, the molar ratio of the total moles of the metallocenecompounds combined to the organoaluminum compound may be from about 1:1to about 1:1,000. According to yet another aspect of this invention, themolar ratio of the total moles of the metallocene compounds combined tothe organoaluminum compound may be from about 1:1 to about 1:100. Thesemolar ratios reflect the ratio of the metallocene compounds to the totalamount of organoaluminum compound in both the precontacted mixture andthe postcontacted mixture combined.

When a precontacting step is used, the molar ratio of olefin monomer tototal moles of metallocene compound combined in the precontacted mixturemay be from about 1:10 to about 100,000:1, for example, from about 10:1to about 1,000:1.

The weight ratio of the activator-support to the organoaluminum compoundmay be from about 1:5 to about 1,000:1. The weight ratio of theactivator-support to the organoaluminum compound may be from about 1:3to about 100:1, for example, from about 1:1 to about 50:1.

According to a further aspect of this invention, the weight ratio of thetotal moles of the metallocene compound combined to theactivator-support may be from about 1:1 to about 1:1,000,000. Accordingto yet another aspect of this invention, the weight ratio of the totalmoles of the metallocene compound combined to the activator-support maybe from about 1:10 to about 1:10,000. According to still another aspectof this invention, the weight ratio of the total moles of themetallocene compound combined to the activator-support may be from about1:20 to about 1:1000.

Aluminoxane compounds are not required to form the catalyst compositionof the present invention. Thus, the polymerization proceeds in theabsence of aluminoxanes. Accordingly, the present invention may useAlR₃-type organoaluminum compounds and an activator-support in theabsence of aluminoxanes. While not intending to be bound by theory, itis believed that the organoaluminum compound likely does not activatethe metallocene catalyst in the same manner as an organoaluminoxane. Asa result, the present invention results in lower polymer productioncosts.

Additionally, no expensive borate compounds or MgCl₂ are required toform the catalyst composition of this invention. Nonetheless,aluminoxanes, organoboron compounds, ionizing ionic compounds,organozinc compounds, MgCl₂, or any combination thereof optionally maybe used in the catalyst composition of this invention. Further,cocatalysts such as aluminoxanes, organoboron compounds, ionizing ioniccompounds, organozinc compounds, or any combination thereof optionallymay be used as cocatalysts with the metallocene compound, either in thepresence or in the absence of the activator-support, and either in thepresence or in the absence of the organoaluminum compound.

According to one aspect of this invention, the catalyst activity of thecatalyst of this invention may be greater than or equal to about 100grams polyethylene per gram of chemically-treated solid oxide per hour(abbreviated gP/(gCTSO·hr)). According to another aspect of thisinvention, the catalyst of this invention may be characterized by anactivity of greater than or equal to about 250 gP/(gCTSO·hr). Accordingto still another aspect of this invention, the catalyst of thisinvention may be characterized by an activity of greater than or equalto about 500 gP/(gCTSO·hr). According to yet another aspect of thisinvention, the catalyst of this invention may be characterized by anactivity of greater than or equal to about 1000 gP/(gCTSO·hr). Accordingto a further aspect of this invention, the catalyst of this inventionmay be characterized by an activity of greater than or equal to about2000 gP/(gCTSO·hr). This activity is measured under slurrypolymerization conditions using isobutane as the diluent, at apolymerization temperature of about 90° C. and an ethylene pressure ofabout 550 psig. The reactor should have substantially no indication ofany wall scale, coating or other forms of fouling upon making thesemeasurements.

Any combination of the metallocene compounds, the activator-support, theorganoaluminum compound, and the olefin monomer, may be precontacted.When any precontacting occurs with an olefinic monomer, it is notnecessary that the olefin monomer used in the precontacting step be thesame as the olefin to be polymerized. Further, when a precontacting stepamong any combination of the catalyst components is employed for a firstperiod of time, this precontacted mixture may be used in a subsequentpostcontacting step between any other combination of catalyst componentsfor a second period of time. For example, all the catalyst componentsand 1-hexene may be used in a precontacting step for a first period oftime, and this precontacted mixture may then be contacted with theactivator-support to form a postcontacted mixture that is contacted fora second period of time prior to initiating the polymerization reaction.For example, the first period of time for contact, the precontact time,between any combination of the metallocene compounds, the olefinicmonomer, the activator-support, and the organoaluminum compound may befrom about 0.1 hour to about 24 hours, for example, from about 0.1 toabout 1 hour. Precontact times from about 10 minutes to about 30 minutesare also typical. The postcontacted mixture optionally may be allowed toremain in contact for a second period of time, the postcontact time,prior to initiating the polymerization process. According to one aspectof this invention, postcontact times between the precontacted mixtureand any remaining catalyst components may be from about 0.1 hour toabout 24 hours, for example, from about 0.1 hour to about 1 hour.

D. Use of the Catalyst Composition in Polymerization Processes

After catalyst activation, the catalyst composition is used tohomopolymerize ethylene or copolymerize ethylene with a comonomer.

The polymerization temperature may be from about 60° C. to about 280°C., for example, from about 70° C. to about 110° C. The polymerizationreaction typically begins in an inert atmosphere substantially free ofoxygen and under substantially anhydrous conditions. For example, a dry,inert atmosphere such as dry nitrogen or dry argon may be used.

The polymerization reaction pressure may be any pressure that does notterminate the polymerization reaction, and is typically a pressurehigher than the pretreatment pressures. According to one aspect of thepresent invention, the polymerization pressure may be from aboutatmospheric pressure to about 1000 psig. According to another aspect ofthe present invention, the polymerization pressure may be from about 50psig to about 800 psig. Further, hydrogen can be used in thepolymerization process of this invention to control polymer molecularweight.

Polymerizations using the catalysts of this invention may be carried outin any manner known in the art. Such processes that may be suitable foruse with the present invention include, but are not limited to, slurrypolymerizations, gas phase polymerizations, solution polymerizations,and multi-reactor combinations thereof. Thus, any polymerization zoneknown in the art to produce olefin-containing polymers can be utilized.For example, a stirred reactor may be utilized for a batch process, or aloop reactor or a continuous stirred reactor may be used for acontinuous process.

A typical polymerization method is a slurry polymerization process (alsoknown as the particle form process), which is well known in the art andis disclosed, for example, in U.S. Pat. No. 3,248,179, incorporated byreference herein in its entirety. Other polymerization methods of thepresent invention for slurry processes are those employing a loopreactor of the type disclosed in U.S. Pat. No. 3,248,179, incorporatedby reference herein in its entirety, and those utilized in a pluralityof stirred reactors either in series, parallel, or combinations thereof,where the reaction conditions are different in the different reactors.Suitable diluents used in slurry polymerization are well known in theart and include hydrocarbons that are liquids under reaction conditions.The term “diluent” as used in this disclosure does not necessarily meanan inert material, as this term is meant to include compounds andcompositions that may contribute to polymerization process. Examples ofhydrocarbons that may be used as diluents include, but are not limitedto, cyclohexane, isobutane, n-butane, propane, n-pentane, isopentane,neopentane, and n-hexane. Typically, isobutane may be used as thediluent in a slurry polymerization, as provided by U.S. Pat. Nos.4,424,341, 4,501,885, 4,613,484, 4,737,280, and 5,597,892, each of whichis incorporated by reference herein in its entirety.

Various polymerization reactors are contemplated by the presentinvention. As used herein, “polymerization reactor” includes anypolymerization reactor or polymerization reactor system capable ofpolymerizing olefin monomers to produce homopolymers or copolymers ofthe present invention. Such reactors may be slurry reactors, gas-phasereactors, solution reactors, or any combination thereof. Gas phasereactors may comprise fluidized bed reactors or tubular reactors. Slurryreactors may comprise vertical loops or horizontal loops. Solutionreactors may comprise stirred tank or autoclave reactors.

Polymerization reactors suitable for the present invention may compriseat least one raw material feed system, at least one feed system forcatalyst or catalyst components, at least one reactor system, at leastone polymer recovery system or any suitable combination thereof.Suitable reactors for the present invention further may comprise anyone, or combination of, a catalyst storage system, an extrusion system,a cooling system, a diluent recycling system, or a control system. Suchreactors may comprise continuous take-off and direct recycling ofcatalyst, diluent, and polymer. Generally, continuous processes maycomprise the continuous introduction of a monomer, a catalyst, and adiluent into a polymerization reactor and the continuous removal fromthis reactor of a suspension comprising polymer particles and thediluent.

Polymerization reactor systems of the present invention may comprise onetype of reactor per system or multiple reactor systems comprising two ormore types of reactors operated in parallel or in series. Multiplereactor systems may comprise reactors connected together to performpolymerization or reactors that are not connected. The polymer may bepolymerized in one reactor under one set of conditions, and thentransferred to a second reactor for polymerization under a different setof conditions.

According to one aspect of the invention, the polymerization reactorsystem may comprise at least one loop slurry reactor. Such reactors areknown in the art and may comprise vertical or horizontal loops. Suchloops may comprise a single loop or a series of loops. Multiple loopreactors may comprise both vertical and horizontal loops. The slurrypolymerization is typically performed in an organic solvent that candisperse the catalyst and polymer. Examples of suitable solvents includebutane, hexane, cyclohexane, octane, and isobutane. Monomer, solvent,catalyst and any comonomer may be continuously fed to a loop reactorwhere polymerization occurs. Polymerization may occur at lowtemperatures and pressures. Reactor effluent may be flashed to removethe solid resin.

According to yet another aspect of this invention, the polymerizationreactor may comprise at least one gas phase reactor. Such systems mayemploy a continuous recycle stream containing one or more monomerscontinuously cycled through the fluidized bed in the presence of thecatalyst under polymerization conditions. The recycle stream may bewithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product may be withdrawn from the reactor andnew or fresh monomer may be added to replace the polymerized monomer.Such gas phase reactors may comprise a process for multi-step gas-phasepolymerization of olefins, in which olefins are polymerized in thegaseous phase in at least two independent gas-phase polymerization zoneswhile feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone.

According to still another aspect of the invention, the polymerizationreactor may comprise a tubular reactor. Tubular reactors may makepolymers by free radical initiation, or by employing the catalyststypically used for coordination polymerization. Tubular reactors mayhave several zones where fresh monomer, initiators, or catalysts areadded. Monomer may be entrained in an inert gaseous stream andintroduced at one zone of the reactor. Initiators, catalysts, and/orcatalyst components may be entrained in a gaseous stream and introducedat another zone of the reactor. The gas streams may be intermixed forpolymerization. Heat and pressure may be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another aspect of the invention, the polymerizationreactor may comprise a solution polymerization reactor. During solutionpolymerization, the monomer is contacted with the catalyst compositionby suitable stirring or other means. A carrier comprising an inertorganic diluent or excess monomer may be employed. If desired, themonomer may be brought in the vapor phase into contact with thecatalytic reaction product, in the presence or absence of liquidmaterial. The polymerization zone is maintained at temperatures andpressures that will result in the formation of a solution of the polymerin a reaction medium. Agitation may be employed during polymerization toobtain better temperature control and to maintain uniform polymerizationmixtures throughout the polymerization zone. Adequate means are utilizedfor dissipating the exothermic heat of polymerization. Thepolymerization may be effected in a batch manner, or in a continuousmanner. The reactor may comprise a series of at least one separator thatemploys high pressure and low pressure to separate the desired polymer.

According to a further aspect of the invention, the polymerizationreactor system may comprise the combination of two or more reactors.Production of polymers in multiple reactors may include several stagesin at least two separate polymerization reactors interconnected by atransfer device making it possible to transfer the polymers resultingfrom the first polymerization reactor into the second reactor. Thedesired polymerization conditions in one of the reactors may bedifferent from the operating conditions of the other reactors.Alternatively, polymerization in multiple reactors may include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Such reactors may include any combinationincluding, but not limited to, multiple loop reactors, multiple gasreactors, a combination of loop and gas reactors, a combination ofautoclave reactors or solution reactors with gas or loop reactors,multiple solution reactors, or multiple autoclave reactors.

After the polymer is produced, it may be formed into various articles,including but not limited to, household containers, utensils, filmproducts, drums, fuel tanks, pipes, geomembranes, and liners. Variousprocesses may be used to form these articles. Usually, additives andmodifiers are added to the polymer in order to provide desired effects.By using the invention described herein, articles can likely be producedat a lower cost, while maintaining most or all of the unique propertiesof polymers produced with metallocene catalysts.

E. Pipe Extrusion

According to one aspect, a method of making a PE-100 pipe is encompassedby the present invention, the method comprising extruding the polymer orcopolymer in a molten state through a die to form the PE-100 pipe andcooling the pipe.

According to yet other aspects, a PE-100 pipe comprising the polymer orcopolymer of the present invention is contemplated.

Pipe extrusion in the simplest terms is performed by melting, conveyingpolyethylene pellets into a particular shape (generally an annularshape), and solidifying that shape during a cooling process. There arenumerous steps to pipe extrusion as provided below.

The polymer feedstock can either be a pre-pigmented polyethylene resinor it can be a mixture of natural polyethylene and color concentrate(referred to as “Salt and Pepper blends”). In North American, the mostcommon feedstock for pipe extrusion is “Salt and Pepper blends”. InEurope and other areas of the world, the most common feedstock for pipeextrusion is pre-pigmented polyethylene resin. Feedstock is rigidlycontrolled to obtain the proper finished product (pipe) and ultimateconsumer specifications.

The feedstock is then fed into an extruder. The most common extrudersystem for pipe production is a single-screw extruder. The purpose ofthe extruder is to melt, convey and homogenize the polyethylene pellets.Extrusion temperatures typically range from 178° C. to 232° C. dependingupon the extruder screw design and flow properties of the polyethylene.

The molten polymer is then passed through a die. The die distributes thehomogenous polyethylene polymer melt around a solid mandrel, which formsit into an annular shape. Adjustments can be made at the die exit to tryto compensate for polymer sag through the rest of the process.

In order for the pipe to meet the proper dimensional parameters, thepipe is then sized. There are two methods for sizing: vacuum orpressure. Both employ different techniques and different equipment.

Next, the pipe is cooled and solidified in the desired dimensions.Cooling is accomplished by the use of several water tanks where theoutside pipe is either submerged or water is sprayed on the pipeexterior. The pipe is cooled from the outside surface to the insidesurface. The interior wall and inside surfaces of the pipe can stay veryhot for a long period of time, as polyethylene is a poor conductor ofheat.

Finally, the pipe is printed and either coiled or cut to length.

The present invention is further illustrated by the following examples,which are not to be construed in any way as imposing limitations uponthe scope thereof. On the contrary, it is to be clearly understood thatresort may be had to various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maybe suggested to one of ordinary skill in the art without departing fromthe spirit of the present invention or the scope of the appended claims.

EXAMPLES

For each of the following examples, testing procedures were as follows.

Melt index (MI, g/10 min) was determined in accordance with ASTM D1238condition F at 190° C. with a 2,160 gram weight.

High load melt index (HLMI, g/10 min) was determined in accordance withASTM D1238 condition E at 190° C. with a 21,600 gram weight.

Polymer density was determined in grams per cubic centimeter (g/cc) on acompression molded sample, cooled at about 15° C. per hour, andconditioned for about 40 hours at room temperature in accordance withASTM D1505 and ASTM D1928, procedure C.

Melt rheological characterizations were performed as follows.Small-strain (10%) oscillatory shear measurements were performed on aRheometrics Scientific, Inc. ARES rheometer using parallel-plategeometry. All rheological tests were performed at 190° C. The complexviscosity |η*| versus frequency (ω) data were then curve fitted usingthe modified three parameter Carrie-Yasuda (CY) empirical model toobtain the zero shear viscosity—η₀, characteristic viscous relaxationtime—τ_(η), and the breadth parameter—a. The simplified Yasuda-Yasuda(CY) empirical model is as follows.

${{{\eta^{*}(\omega)}} = \frac{\eta_{0}}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{{({1 - n})}/a}}},$

wherein:

-   -   |η*(ω)|=magnitude of complex shear viscosity;    -   η₀=zero shear viscosity;    -   τ_(η)=viscous relaxation time;    -   a=“breadth” parameter;    -   n=fixes the final power law slope, fixed at 2/11; and    -   ω=angular frequency of oscillatory shearing deformation. Details        of the significance and interpretation of the CY model and        derived parameters may be found in: C. A. Hieber and H. H.        Chiang, Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H.        Chiang, Polym. Eng. Sci., 32, 931 (1992); and R. B. Bird, R. C.        Armstrong and O. Hasseger, Dynamics of Polymeric Liquids, Volume        1, Fluid Mechanics, 2nd Edition, John Wiley & Sons (1987); each        of which is incorporated herein by reference in its entirety.        The CY “a” parameter is reported in the tables for the resins        disclosed herein.

A “Quantachrome Autosorb-6 Nitrogen Pore Size Distribution Instrument”was used to determined specific surface area (“surface area”) andspecific pore volume (“pore volume”). This instrument was acquired fromthe Quantachrome Corporation, Syosset, N.Y.

Molecular weights and molecular weight distributions were obtained usinga PL 220 SEC high temperature chromatography unit (Polymer Laboratories)with trichlorobenzene (TCB) as the solvent, with a flow rate of 1mL/minute at a temperature of 145° C. BHT(2,6-di-tert-butyl-4-methylphenol) at a concentration of 0.5 g/L wasused as a stabilizer in the TCB. An injection volume of 200 μL was usedwith a nominal polymer concentration of 1.5 mg/mL. Dissolution of thesample in stabilized TCB was carried out by heating at 150° C. for 5hours with occasional, gentle agitation. The columns used were threePLgel Mixed A LS columns (7.8×300 mm) and were calibrated with a broadlinear polyethylene standard (Phillips Marlex® BHB 5003) for which themolecular weight had been determined.

Molecular weight distributions and branch profiles were obtained throughsize exclusion chromatography using an FTIR detector. Chromatographicconditions

are those described above. However, the sample injection volume was 500μL. Samples were introduced to the FTIR detector via a heated transferline and flow cell (KBr windows, 1 mm optical path, and ca. 70 μL cellvolume). The temperatures of the transfer line and flow cell were keptat 143±1° C. and 140±1° C., respectively. Perkin Elmer FTIRspectrophotometer (PE 2000) equipped with a narrow band mercury cadmiumtelluride (MCT) detector was used in these studies.

All spectra were acquired using Perkin Elmer Timebase software.Background spectra of the TCB solvent were obtained prior to each run.All IR spectra were measured at 8 cm⁻¹ resolution (16 scans).Chromatograms were generated using the root mean square absorbance overthe 3000-2700 cm⁻¹ spectral region (i.e., FTIR serves as a concentrationdetector). Molecular weight calculations were made as previouslydescribed using a broad molecular weight polyethylene (PE) standard [seeJordens K, Wilkes G L, Janzen J, Rohlfing D C, Welch M B. Polymer 2000;41:7175]. Spectra from individual time slices of the chromatogram aresubsequently analyzed for comonomer branch levels using chemometrictechniques. All calibration spectra were taken at sample concentrationswhich far exceeded that needed for good signal to noise (i.e., >0.08mg/mL at the detector).

Branching determination was made as follows. Narrow molecular weight(M_(w)/M_(n)˜1.1 to 1.3), solvent gradient fractions of ethylene1-butene, ethylene 1-hexene, polyethylene homopolymers, and lowmolecular weight alkanes were used in calibration and verificationstudies. The total methyl content of these samples ranged from 1.4 to82.7 methyls per 1000 total carbons. Methyl content of samples wascalculated from M_(n) or measured using C-13 NMR spectroscopy. C-13 NMRspectra were obtained on 15 wt. % samples in TCB using a 500 MHz VarianUnity Spectometer run at 125° C. as previous described [see Randall J C,Hsieh E T, NMR and Macromolecules; Sequence, Dynamic, and DomainStructure, ACS Symposium Series 247, J. C. Randall, Ed., AmericanChemical Society, Washington D.C., 1984.]. Methyl content per 1000carbons by NMR was obtained by multiplying (×1000) the ratio of totalmethyl signals to total signal intensity.

A partial least squares (PLS) calibration curve was generated usingPirouette chemometric software (Infometrix) to correlate changes in theFTIR absorption spectra with calculated or NMR measured values formethyls/1000 total carbons for the 25 samples. The FTIR absorptionspectra used in the calibration model were made from co-added spectracollected across the whole sample. Only a portion of the spectral region(2996 and 2836 cm⁻¹) was used in the calibration step in order tominimize the effects of residual solvent absorption. Preprocessing ofspectral data included area normalization, taking the first derivativeof the spectra and mean centering all data.

A four component calibration model was calculated and optimized usingthe process of cross validation (RSQ=0.999, SEV=0.7). The calibrationmodel was verified using 23 additional samples. The predicted versusactual values for the validation data showed excellent correlation(RSQ=0.987) and exhibited a root mean square error of prediction equalto +/−0.4 methyl groups per 1000 total carbon molecules.

Short chain branching levels were calculated by subtracting out methylchain end contributions. The amount of methyl chain ends were calculatedusing the equation Me_(cc)=C(2−V_(cc))/M, where Me_(cc) is the number ofmethyl chain ends per 1000 total carbon molecules, C is a constant equalto 14000, V_(cc) is the number of vinyl terminated chain ends (1 forchromium catalyzed resins), and M is the molecular weight calculated fora particular slice of the molecular weight distribution.

PENT slow crack growth resistance values were obtained at 80° C. (176°F.) according to ASTM F1473 (2001), with the exception that the initialload was 3.8 MPa, in order to accelerate the test. This 3.8 MPa PENTtest may be referred to herein as a “high stress” PENT test.

The Charpy testing was the Razor-Notched Room-Temperature Charpy Energytest carried out according to ASTM F2231.

Preparation of Cyclopentadienyl Complexes and Metallocene Compounds

The cyclopentadienyl complexes and metallocenes used in the variousexamples or described herein were purchased or prepared as follows. Allmanipulations involving air-sensitive reagents and materials wereperformed under nitrogen by using standard Schlenk line or dry boxtechniques. The solvent THF was distilled from potassium, whileanhydrous diethyl ether, methylene chloride, pentane, and toluene(Fisher Scientific Company) were stored over activated alumina. Allsolvents were degassed and stored under nitrogen. Zirconium (IV)chloride (99.5%) and n-butyllithium were purchased from Aldrich ChemicalCompany and were used as received. Products were analyzed by ¹H NMR (300MHz, CDCl₃, referenced against residual CHCl₃ peak at 7.24 ppm) or ¹³CNMR (75 MHz, CDCl₃, referenced against central line of CDCl₃ at 77.00ppm).

Preparation of Sulfated Alumina Activator-Support

Alumina A, from W. R. Grace Company, was impregnated to incipientwetness with an aqueous solution of ammonium sulfate. Typically, thealumina had a surface area of about 330 m²/gram and a pore volume ofabout 1.3 cc/gram. The amount of ammonium sulfate used was equal to 20%of the starting alumina. The volume of water used to dissolve theammonium sulfate was calculated from the total pore volume of thestarting sample (i.e. 2.6 mLs of water for each gram of alumina to betreated). Thus, a solution of about 0.08 grams of ammonium sulfate permL of water was employed. The resulting wet sand was dried in a vacuumoven overnight at 120° C., and then screened through a 35 mesh screen.Finally, the material was activated in a fluidizing stream of dry air at550° C. for 3 hours, in the case of bench scale samples, or 6 hours, forthe larger pilot plant samples. The samples were then stored undernitrogen.

Example 1 Room Temperature Synthesis of Zr[η-C₅H₄-(nBu)]Cl₃

Zr[η-C₅H₄-(nBu)]Cl₃ was prepared as described in Example 2, except thatthe refluxing step was omitted. Instead, the (n-BuCp)₂ZrCl₂ and ZrCl₄mixture was stirred at ambient temperature for 20 hrs. FIG. 1 presentsthe NMR spectrum for the Zr[η-O₅H₄-(nBu)]Cl₃ formed according toExample 1. The molar ratio obtained for the product Zr[η-O₅H₄-(nBu)]Cl₃to starting material (n-BuCp)₂ZrCl₂ was 1.4:1.

Example 2 Inventive Preparation of Zr[η-C₅H₄-(nBu)]Cl₃

A 500 mL Schlenk flask was charged with (n-BuCp)₂ZrCl₂ (20.0 g, 49.4mmol), ZrCl₄ (12.7 g, 54.4 mmol), 300 mL of toluene and a stir bar. Theresulting yellow slurry was refluxed under N₂ for about 20 h. The darkbrown-black reaction mixture was centrifuged to remove excess ZrCl₄ andtoluene was removed from the filtrate under reduced pressure to obtain abrown-black thick oil. The product was precipitated a couple of timeswith a CH₂Cl₂/pentane mixture and vacuum-dried (0.1 mm, 1 h) to affordthe desired product as a brown solid. (27 g, 87%). FIG. 2 presents theNMR spectrum for the Zr[η-O₅H₄-(nBu)]Cl₃ formed according to Example 2.The molar ratio obtained for the product Zr[η-O₅H₄-(nBu)]Cl₃ to startingmaterial (n-BuCp)₂ZrCl₂ was 52:1. Thus, the method of makingZr[η-C₅H₄-(nBu)]Cl₃ according to the present invention significantlyimproves the yield and selectivity of the reaction.

Example 3 Preparation of Zr[η-C₅H₃-(nBu, Me)1,3]Cl₃

A 500 mL Schlenk flask was charged with (1,3 Me,nBuCp)₂ZrCl₂ (20.0 g,46.2 mmol), ZrCl₄ (11.9 g, 50.7 mmol), 200 mL of toluene and a stir bar.Resulting yellow slurry was refluxed under N₂ for about 20 h. Darkbrown-black reaction mixture was centrifuged to remove excess ZrCl₄ andtoluene was removed from the filtrate under reduced pressure to obtain abrown-black thick oil. The product was precipitated a couple of timeswith a CH₂Cl₂/pentane mixture and vacuum-dried (0.1 mm, 1 h) to affordthe desired product as a brown solid. (23 g, 76%). ¹H NMR (CDCl₃, δ)0.94 (t, J=7.5 Hz, CH₃), 1.62-1.31 (m, CH₂(CH₂)₂CH₃), 2.44 (s, CH₃),2.81-2.75 (m, CH₂(CH₂)₂CH₃), 6.24 (broad s, 1, C₅H₄), 6.45 (broad s, 2,C₅H₄).

Example 4 Preparation ofZr{η⁵-C₅H₄-[(CH₂)₃CH₃]}{η⁵-C₉H₆-1-(CH₂CH═CH₂)}Cl₂

A 500 mL Schlenk flask was charged with nBuCpZrCl₃ (20.0 g, 62.7 mmol)and approximately 400 mL of diethyl ether. The resulting slurry wascooled to 0° C., after which time (10.7 g, 66.0 mmol) ofLi[(C₉H₆)-1(allyl)] was cannulated as an ethereal solution. The reactionmixture was stirred overnight at ambient temperature and the solvent wasremoved in vacuo. The resulting solid was dissolved in toluene andcentrifuged to remove LiCl. Removal of solvent in vacuo yielded ayellow-brown solid which was dissolved in a dichloromethane/pentanemixture and was cooled to −35° C. for a couple of hours. Resultingslurry was filtered, and the precipitate was dried under reducedpressure (0.1 mm, 1 h) to yield the product as a yellow solid (17.0 g,62%). ¹H NMR (CDCl₃, δ) 0.87 (t, J=7.2 Hz, CH₃), 1.50-1.22 (m,CH₂(CH₂)₂CH₃), 2.58-2.42 (m, CH₂(CH₂)₂CH₃), 3.77-3.62 (m, CH₂═CHCH₂),5.10-5.02 (m, CH₂═CHCH₂), 5.78-5.76 (m, 1, C₅H₄), 5.87-5.83 (m, 2,C₅H₄), 5.99-5.91 (m, CH₂═CHCH₂), 6.04-6.00 (m, 1, C₅H₄), 6.39-6.37 (m,1, C₉H₆), 6.63 (d, J=3.0 Hz, 1, C₉H₆), 7.28-7.18 (m, 2, C₉H₆), 7.60-7.56(m, 2, C₉H₆).

Example 5 Preparation ofZr{η⁵-C₅H₄-[(CH₂)₃CH₃]}{η⁵-C₉H₆-1-[(CH₂)₂CH═CH₂]}Cl₂

A 500 mL Schlenk flask was charged with nBuCpZrCl₃ (5.4 g, 17.0 mmol)and approximately 150 mL of diethyl ether. The resulting slurry wascooled to 0° C., after which time (3.0 g, 17.0 mmol) ofLi[(C₉H₆)-1-(butenyl)] was cannulated as an ethereal solution. Thereaction mixture was stirred overnight at ambient temperature and thesolvent was removed in vacuo. The resulting solid was dissolved intoluene and centrifuged to remove LiCl. Removal of solvent in vacuoyielded a yellow-brown solid which was dissolved in adichloromethane/pentane mixture and was cooled to −35° C. for a coupleof hours. Resulting slurry was filtered, and the precipitate was driedunder reduced pressure (0.1 mm, 1 h) to yield the product as a yellowsolid (7.2 g, 93%). ¹H NMR (CDCl₃, δ) 0.79 (t, J=7.2 Hz, CH₃), 1.41-1.14(m, CH₂(CH₂)₂CH₃), 2.49-2.19 (m, 4, CH₂), 3.07-2.84 (m, CH₂), 4.97-4.84(m, CH₂═CHCH₂), 5.65-5.62 (m, 1, C₅H₄), 5.81-5.68 (m, 3, CH₂═CHCH₂,C₅H₄), 5.95-5.91 (m, 1, C₅H₄), 6.30-6.29 (m, 1, C₉H₆), 6.56 (d, J=3.3Hz, 1, C₉H₆), 7.20-7.11 (m, 2, C₉H₆), 7.53-7.49 (m, 2, C₉H₆).

Example 6 Preparation ofZr{η⁵-C₅H₄-[(CH₂)₃CH₃]}{η⁵-C₉H₆-1-[(CH₂)₃Ph]}Cl₂

A 500 mL Schlenk flask was charged with nBuCpZrCl₃ (19.9 g, 62.4 mmol)and approximately 400 mL of diethyl ether. The resulting slurry wascooled to 0° C., after which time (15.0 g, 62.4 mmol) ofLi[(C₉H₆)-1-(3-phenylpropyl)] was cannulated as an ethereal solution.The reaction mixture was stirred overnight at ambient temperature andthe solvent was removed in vacuo. The resulting solid was dissolved intoluene and centrifuged to remove LiCl. Removal of solvent in vacuoyielded a yellow-brown solid which was dissolved in adichloromethane/pentane mixture and was cooled to −35° C. for a coupleof hours. Resulting slurry was filtered, and the precipitate was driedunder reduced pressure (0.1 mm, 1 h) to yield the product as a yellowsolid (23.6 g, 73%). ¹H NMR (CDCl₃, δ) 0.80 (t, J=7.2 Hz, CH₃),1.42-1.15 (m, CH₂(CH₂)₂CH₃), 1.96-1.84 (m, 2, CH₂), 2.49-2.34 (m,CH₂(CH₂)₂CH₃), 2.69-2.53 (m, 2, CH₂), 3.03-2.80 (m, 2, CH₂), 5.64-5.62(m, 1, C₅H₄), 5.75-5.71 (m, 2, C₅H₄), 5.93-5.91 (m, 1, C₅H₄), 6.31-6.30(m, 1, C₉H₆), 6.56 (d, J=3.3 Hz, 1, C₉H₆), 7.20-7.05 (m, 7, C₉H₆, C₆H₅),7.53-7.46 (m, 2, C₉H₆).

Example 7 Preparation ofZr{η⁵-C₅H₄—[(CH₂)₃CH₃]}{η⁵-C₉H₆-1-[CH₂)₃PH₃]}Cl₂

A 500 mL Schlenk flask was charged with nBuCpZrCl₃ (5.4 g, 16.8 mmol)and approximately 150 mL of diethyl ether. The resulting slurry wascooled to 0° C., after which time (3.0 g, 16.8 mmol) ofLi[(C₉H₆)-1-(butyl)] was cannulated as an ethereal solution. Thereaction mixture was stirred overnight at ambient temperature and thesolvent was removed in vacuo. The resulting solid was dissolved intoluene and centrifuged to remove LiCl. Removal of solvent in vacuoyielded a yellow-brown solid which was dissolved in adichloromethane/pentane mixture and was cooled to −35° C. for a coupleof hours. Resulting slurry was filtered, and the precipitate was driedunder reduced pressure (0.1 mm, 1 h) to yield the product as a yellowsolid (3.7 g, 48%). ¹H NMR (CDCl₃, δ) 0.88-0.78 (m, 6, CH₃), 1.58-1.15(m, 8, CH₂), 2.50-2.35 (m, CH₂(CH₂)₂CH₃), 2.99-2.73 (m, 2, CH₂),5.67-5.64 (m, 1, C₅H₄), 5.77-5.73 (m, 2, C₅H₄), 5.96-5.92 (m, 1, C₅H₄),6.31-6.30 (m, 1, C₉H₆), 6.56 (d, J=3.3 Hz, 1, C₉H₇), 7.21-7.09 (m, 2,C₉H₇), 7.54-7.49 (m, 2, C₉H₇).

Example 8 Preparation of Zr{η⁵-C₅H₄—[(CH₂)₃CH₃]}{η⁵-C₉H₇}Cl₂

A 500 mL Schlenk flask was charged with nBuCpZrCl₃ (1.0 g, 3.1 mmol) andapproximately 150 mL of diethyl ether. The resulting slurry was cooledto 0° C., after which time (0.4 g, 3.1 mmol) of indenyl lithium wascannulated as an ethereal solution. The reaction mixture was stirredovernight at ambient temperature and the solvent was removed in vacuo.The resulting solid was dissolved in toluene and centrifuged to removeLiCl. Removal of solvent in vacuo yielded a yellow-brown solid which wasdissolved in a dichloromethane/pentane mixture and was cooled to −35° C.for a couple of hours. Resulting slurry was filtered, and theprecipitate was dried under reduced pressure (0.1 mm, 1 h) to yield theproduct as a yellow solid (0.8 g, 64%). ¹H NMR (CDCl₃, δ) 0.81 (t, J=5.0Hz, CH₃), 1.43-1.16 (m, CH₂(CH₂)₂CH₃), 2.47-2.42 (m, CH₂(CH₂)₂CH₃), 5.76(t, J=2.4 Hz, 2, C₅H₄), 5.87 (t, J=2.4 Hz, 2, C₅H₄), 6.42 (d, J=3.0 Hz,2, C₉H₇), 6.82 (t, J=3.3 Hz, 1, C₉H₇), 7.22-7.16 (m, 2, C₉H₇), 7.60-7.56(m, 2, C₉H₇).

Example 9 Preparation of Zr[η⁵-C₅H₃-(nBu,Me)1,3]}{η⁵-C₉H₆-1-(CH₂CH═CH₂)}Cl₂

A 500 mL Schlenk flask was charged with (1,3-MeBuCp)ZrCl₃ (5.0 g, 15.0mmol) and approximately 150 mL of diethyl ether. The resulting slurrywas cooled to 0° C., after which time (2.5 g, 15.0 mmol) ofLi[(C₉H₆)-1(allyl)] was cannulated as an ethereal solution. The reactionmixture was stirred overnight at ambient temperature and the solvent wasremoved in vacuo. The resulting solid was dissolved in toluene andcentrifuged to remove LiCl. Removal of solvent in vacuo yielded ayellow-brown oily solid which was dissolved in pentane, filtered, andfiltrate was cooled to −35° C. Resulting slurry was filtered, and theprecipitate was dried under reduced pressure (0.1 mm, 1 h) to yield theproduct as a yellow, oily solid (3.9 g, 57%). ¹H NMR (CDCl₃, δ)0.85-0.77 (m, 6, CH₃), 1.46-1.12 (m, 8, CH₂(CH₂)₂CH₃), 1.96 (s, CH₃),2.04 (s, CH₃), 2.49-2.11 (m, 4, CH₂(CH₂)₂CH₃), 3.72-3.53 (m, 4,CH₂═CHCH₂), 5.02-4.92 (m, 4, CH₂═CHCH₂), 5.16 (t, J=2.7 Hz, 1, C₅H₄),5.26 (t, J=2.7 Hz, 1, C₅H₄), 5.74-5.70 (m, 2, C₅H₄), 5.87-5.82 (m, 2,C₅H₄), 5.80-5.88 (m, CH₂═CHCH₂), 6.27-6.25 (m, 2, C₉H₆), 6.47-6.46 (m,2, C₉H₆), 7.19-7.09 (m, 4, C₉H₆), 7.51-7.44 (m, 4, C₉H₆).

Example 10 Preparation of1-(methyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methanezirconiumdichloride

1-(Methyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methanezirconiumdichloride can be prepared using numerous techniques. Severaltechniques are described in U.S. patent application Ser. No. 10/876,948for “IMPROVED SYNTHESIS OF ANSA-METALLOCENES AND THEIR PARENT LIGANDS INHIGH YIELD”, incorporated by reference herein in its entirety.

Several techniques for preparing the ligand are provided herein by wayof example and not by way of limitation. The correspondingansa-metallocenes that comprise the ligands disclosed herein areprepared in the usual fashion, according to any one of severalprocedures known in the art, as understood by one of ordinary skill. Forexample, one procedure to prepare the corresponding zirconium dichlorideansa-metallocene from these ligands uses 2 equivalents of n-butyllithium(in hexanes) to treat a stirred diethylether solution of the parentligand, typically at about 0° C. Once the n-butyllithium has been added,the ether solution is typically allowed to warm to room temperatureovernight. The solution of the dilithiated parent ligand is than addedslowly to a slurry of ZrCl₄ in pentane, usually at about 0° C. Thesolvent is removed in vacuo to afford a solid that can be washed withpentane and extracted with dichloromethane or similar solvents.

a. Preparation of1-(methyl)-1-(3-butenyl)-1-cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methanefrom 2,7-di-tert-butylfluorenyl lithium and 6-butenyl-6-methylfulvene

A one-liter flask is charged with 2,7-di-tert-butylfluorene (50 g, 179.6mmol) and a stir bar, capped with a rubber septum, and placed under anitrogen atmosphere. Diethyl ether (about 200 mL) is added via acannula, and the resulting mixture is cooled to −78° C. in a dry-icebath. This mixture is stirred at this temperature as n-butyllithium(19.0 mL of 10 M in hexanes, 190 mmol) is added slowly via syringe.After the addition of n-butyllithium is complete, the reddish solutionis slowly warmed to room temperature and stirred overnight (at leastabout 12 hours). After this time, the reaction mixture is cooled to −78°C., and 6-butenyl-6-methylfulvene (40 mL) is added quickly (in less than1 minute) at this temperature with stirring. Upon completion of thefulvene addition, the mixture is removed from the dry ice bath andwarmed to room temperature, and a GC aliquot is taken after ca. 15minutes following removal of the dry-ice bath.

Stirring is continued for 7 hours, after which time the reaction mixtureis quenched with a saturated NH₄Cl/H₂O solution (300 mL). The organiclayer is extracted with diethyl ether, washed twice with H₂O (500 mL),dried over anhydrous Na₂SO₄, filtered, and the filtrate evaporated todryness to afford a solid. Methanol (ca. 500 mL) is added to the solidand the mixture stirred overnight to form the product as a finelydivided white solid. After filtration, washing with MeOH, and dryingovernight, the desired parent ligand1-(methyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methaneis isolated and may be used without further purification.

b. Preparation of1-(methyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methane—MethodA1

A one-liter flask is charged with 2,7-di-tert-butylfluorene (50 g, 179.6mmol) and a stir bar, capped with a rubber septum, and placed under anitrogen atmosphere. Diethyl ether (about 300 mL) is added via acannula, and the resulting mixture is cooled to −78° C. in a dry-icebath. This mixture is stirred at this temperature as n-butyllithium(21.5 mL of 10 M in hexanes, 215 mmol) is added slowly via syringe.After the addition of n-butyllithium is complete, the reddish solutionis slowly warmed to room temperature and stirred overnight (at leastabout 12 hours), to provide an ether solution of2,7-di-tert-butylfluorenyl lithium.

Another one-liter flask fitted with an addition funnel is charged with6-butenyl-6-methylfulvene (37 g, 253 mmol) and a stir bar, and cooled to0° C. under a nitrogen atmosphere. The ether solution of2,7-di-tert-butylfluorenyl lithium prepared as above is added in adropwise fashion to the fulvene at 0° C. via the addition funnel overthe course of approximately one hour. The resulting dark-coloredreaction mixture is warmed to room temperature and stirred overnight (atleast about 12 hours) under a nitrogen atmosphere. The reaction mixtureis then quenched with the slow addition of a saturated NH₄Cl/H₂Osolution (300 mL), the organic layer extracted with ether, washed twicewith H₂O (500 mL), dried over anhydrous Na₂SO₄, filtered, and thefiltrate evaporated to dryness. The crude product obtained by thismethod is then dissolved in pentane and maintained at about 0° C. in afreezer, thereby affording the product as a white solid that is washedwith cold pentane, dried under vacuum, and isolated and used withoutfurther purification. Further product could be isolated in smallerquantities through concentrating the mother liquors and combinedwashings and placing them back in freezer.

c. Preparation of1-(methyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methane—MethodA2

An ether solution of 2,7-di-tert-butylfluorenyl lithium is prepared andadded in a dropwise fashion over the course of approximately one hour toneat 6-butenyl-6-methylfulvene (at 0° C.) in the same manner as inMethod A1. The resulting reaction mixture is then warmed to roomtemperature and stirred for 2 days under a nitrogen atmosphere. Afterthis time, an additional 5 mL of 6-butenyl-6-methylfulvene and anadditional 30 mL of the n-butyllithium solution are added to thereaction mixture at room temperature. This mixture is stirred overnightat room temperature.

The reaction mixture is then quenched with the slow addition of asaturated NH₄Cl/H₂O solution (300 mL), the organic layer extracted withether, washed twice with H₂O (500 mL), dried over anhydrous Na₂SO₄,filtered, and the filtrate evaporated to dryness. The crude productobtained by this method is dissolved in and crystallized from apentane:Et₂O solution (4:1 mixture by volume) at about 0° C., therebyaffording the product as a white solid.

d. Preparation of1-(methyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methane—MethodA3

A THF solution of 2,7-di-tert-butylfluorenyl lithium is prepared andadded in a dropwise fashion over the course of approximately one hour tothe 6-butenyl-6-methylfulvene solution (at 0° C.) in the same manner asdisclosed in Method A1. The resulting dark-colored reaction mixture iswarmed to room temperature and stirred overnight (at least about 12hours) under a nitrogen atmosphere. This THF reaction mixture is thenquenched with the slow addition of a saturated NH₄Cl/H₂O solution (300mL), the organic layer extracted with diethyl ether, washed twice withH₂O (500 mL), dried over anhydrous Na₂SO₄, filtered, and the filtrateevaporated to dryness. The crude product obtained by this method is thendissolved in and crystallized from pentane at about 0° C., therebyaffording a product as a white solid.

Example 11 Preparation of1-(phenyl)-1-(butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methanezirconiumdichloride

A 1 L round bottomed flask is charged with fluorene (23.2 g, 139.6mmol), THF (400 mL), and a stir bar, and is cooled to −78° C. asn-butyllithium (165 mmol) is slowly added. The mixture is warmed to roomtemperature, stirred overnight, cooled to 0° C., and6-phenyl-6-(5-butenyl)fulvene (38 g, 171 mmol), dissolved in THF, addedvia cannula. After stirring for two days at room temperature thereaction is quenched with saturated NH₄Cl solution, the organic materialextracted with diethyl ether, and the extracts dried over anhydrousNa₂SO₄. Upon solvent removal, a yellow oil is isolated. Chromotographyof this oil through silica using heptane affords the desired ligand thatmay be used without further purification.

Example 12 Comparison of Inventive Catalysts with Ind₂ZrCl₂

Various polymerization runs were conducted to demonstrate the supportactivity of various metallocenes of the present invention compared withthe support activity of bis-indenyl zirconiumdichloride (obtained fromWitco under the trade name Eurecen 5032).

All laboratory polymerization runs were conducted in a one-gallon (3.785liter) stainless steel reactor. The reactor employed an air-operatedstirrer with a three bladed propeller and was set to run at 1180 rpm forthe duration of a run. The reactor was also encased in a steel jacketwith supply lines leading to a heat exchange unit, that was in turnconnected to cooling water and a steam line, allowing for temperaturecontrol.

The initiation of the charging sequence to the reactor was through anopened charge port while venting with isobutane vapor. An alkylaluminumwas injected, quickly followed by addition of the solid activator andcatalyst solution. The charge port was closed and 20 psi isobutane vaporadded. A side vessel was utilized to hold a measured amount of hexeneand this was pushed into the reactor with two liters of isobutane liquidbacked by nitrogen pressure. The contents of the reactor were stirredand heated to 2 degrees Centigrade below the desired run temperature,and ethylene was then introduced. A mass flow unit allowed the pressureto climb quickly to 5 psi below the required run pressure, and allowedthe smooth transition of ethylene flow until the specified temperature(90° C.) and reactor pressure (450 psi) levels were achieved. Thereactor pressure was maintained by addition of ethylene on demand. Thesetemperature and pressure levels were maintained for the duration of therun (30 min). At the completion of the run time the ethylene flow wasstopped and the reactor pressure slowly vented off. When the pressureand temperature were safely low enough the reactor was opened and thegranular polymer powder collected. Activity was specified as grams ofpolymer produced per gram of solid activator charged per hour. A summaryof the various runs is presented in Table 1.

TABLE 1 Cat. 1- Support wt. R₃Al Time Hexene Support Solid Activity MIHLMI Run Catalyst (mg) (ml) (min) (g) Support (mg) PE (g) (g/g/h) (g/10min) g/10 min 12-1 G 1.5 TNBAL 1 30 10 Sulfated 50 227 9080 0.09 2.36Al₂O₃ 12-2 G 1.5 TIBA 1 30 10 Sulfated 50 136 5440 0.05 1.5 Al₂O₃ 12-3 H1.5 TIBA 1 30 10 Sulfated 50 177 7080 0 0.87 Al₂O₃ 12-4 J 1.5 TNBAL 1 3010 Sulfated 50 90 3600 0.03 1.18 Al₂O₃ 12-5 J 1.5 TIBA 1 30 10 Sulfated50 87 3480 0.01 0.78 Al₂O₃ 12-6 K 1.5 TNBAL 1 60 10 Sulfated 50 210 42000.09 2.02 Al₂O₃ 12-7 L 3 TIBA 1 30 10 Sulfated 100 177 3540 0 1.76 Al₂O₃12-8 P 3 TIBA 1 30 10 Sulfated 100 130 2600 0.01 0.56 Al₂O₃ 12-9Ind₂ZrCl₂ 3 TIBA 1 30 10 Sulfated 100 219 4380 0 1 Al₂O₃ 12-10 Ind₂ZrCl₂2 TNBAL 1 30 10 Sulfated 100 175 3500 0.37 6.76 Al₂O₃

As shown in Table 1, inventive catalysts G (Runs 12-1 and 12-2) and H

(Run 12-3), each having an indenyl with a substituent at the 1-positionincorporating a terminal olefin, and a mono-substitutedcyclopentadienyl, display from about 25 to about 60% higherpolymerization activities (support activity) than Ind₂ZrCl₂ undersimilar conditions (Runs 12-9 and 12-10).

Additionally, polymers produced by metallocene compounds G and J, andInd₂ZrCl₂ were evaluated using ¹³C NMR to determine the level of1-hexene incorporation (Runs 12-11 to 12-15). Ind₂ZrCl₂ generally isconsidered to be a poor comonomer incorporating catalyst. The results ofthe evaluation are presented Table 2 and illustrated in FIG. 3. As isevident from the data presented, there is a nearly 50% drop in 1-hexeneincorporation in the polymers formed using metallocene compounds G and Jcompared with the polymer formed using Ind₂ZrCl₂.

TABLE 2 Cat. Solid 1-Hexene Wt. 1-Hexene R₃Al Support PE MI HLMI (butylRun Catalyst (mg) (g) (mL) Support (mg) (g) (g/10 min) (g/10 min) mole%) 12-11 Ind2ZrCl2 1.5 10 TIBA Sulfated 50 101 0.04 3.32 0.13 Al₂O₃12-12 G 1.5 10 TIBA Sulfated 50 117 0.09 2.24 0.08 Al₂O₃ 12-13 J 3.0 10TIBA Sulfated 100 340 0 0.88 0.066 Al₂O₃ 12-14 Ind2ZrCl2 2.0 25 TIBASulfated 100 246 0.43 11.02 0.37 Al₂O₃ 12-15 J 3.0 25 TIBA Sulfated 100258 0.20 5.47 0.19 Al₂O₃

Example 13

Pilot plant polymerizations were conducted to demonstrate the ability touse dual metallocene catalysts systems according to the presentinvention to form a bimodal polymer. Metallocene compound C was used toform the high molecular weight component and metallocene compound G wasused to form the low molecular weight component.

To prepare a solution of metallocene C, 2.00 g of solid metallocene C,1-(phenyl)-1-(3-butenyl)-1-(cyclopentadienyl)-1-(2,7-di-tert-butylfluorenyl)methane zirconium dichloride, was slurried in about 200 mL ofhexene-1, followed by addition of 25 grams of neat (93%)triethylaluminum, under nitrogen. This solution was diluted with 100 to240 grams of n-heptane and transferred to a steel vessel. Isobutane wasadded to obtain a total of 40 pounds of solution.

To prepare a solution of metallocene G, 2.00 g of solid metallocene Gwas dissolved in 420 mL of toluene under nitrogen. The solution wastransferred to a steel vessel. Isobutane was added to obtain a total of40 pounds of solution.

Tri-n-butylaluminum (TNBAL) (obtained from Akzo Corporation) was used asa co-catalyst. The TNBAL was obtained as a neat solution and was dilutedto 10 weight percent with heptane. The cocatalyst was added in aconcentration in a range of from about 8 to about 26 parts per millionof the diluent in the polymerization reactor(s). To prevent staticbuildup in the reactor, a small amount (less than 5 ppm by weight ofdiluent) of a commercial antistatic agent sold as “Stadis 450” wasusually added.

The pilot plant polymerizations were conducted in a 23-gallon slurryloop reactor at a production rate of approximately 25 pounds of polymerper hour. Polymerization runs were carried out under continuous particleform process conditions in a loop reactor (also known as a slurryprocess) by contacting a metallocene solution, tri-n-butylaluminum, anda solid activator in a 300 mL stirred autoclave with continuous outputto the loop reactor.

The precontacting was carried out in the following manner.Tri-n-butylaluminum solution and metallocene solution were fed asseparate streams into a tee upstream of the autoclave where theycontacted each other. The solid activator (sulfated alumina) was flushedwith isobutane into a tee between the aforementioned tee and theautoclave, contacting the tri-n-butylaluminum/metallocene mixture justbefore entering the autoclave. The isobutane flush used to transport thesolid activator into the autoclave was set at a rate that would resultin a residence time of approximately 25 minutes in the autoclave. Thetotal flow from the autoclave then entered the loop reactor.

Ethylene used was polymerization grade ethylene (obtained from UnionCarbide Corporation) which was purified through a column of alumina andactivated at 250° C. (482° F.) in nitrogen. 1-Hexene, when used, waspolymerization grade 1-hexene (obtained from Chevron Phillips ChemicalCompany LP) which was purified by nitrogen purging and storage over 13×molecular sieve activated at 250° C. (482° F.) in nitrogen. The loopreactor was a liquid full, 15.2 cm diameter, loop reactor, having avolume of 23 gallons (87 liters). Liquid isobutane was used as thediluent. Some hydrogen was added to regulate the molecular weight of thelow molecular weight component of the polymer product. The isobutane waspolymerization grade isobutane (obtained from Chevron Phillips Chemical,Borger, Tex.) that was further purified by distillation and subsequentlypassed through a column of alumina (activated at 250° C. (482° F.) innitrogen).

Reactor conditions included a pressure around 580 psi (4 MPa), and atemperature that was varied from about 90° C. (194° F.) to about 99° C.(210° F.). Also, the reactor was operated to have a residence time ofabout 1 hour. The solid activator was added through a 0.35 cccirculating ball-check feeder and fed to the 300 mL autoclave asdescribed above. Catalyst system concentrations in the reactor werewithin a range of about 1 to 2 parts per million (ppm) of the diluent inthe polymerization reactor. Polymer was removed from the reactor at therate of about 25 lbs per hour and recovered in a flash chamber. A Vulcandryer was used to dry the polymer under nitrogen at about 60 to about80° C. (about 40 to about 176° F.).

Various resins were prepared according to the above procedure. Theresults of the evaluation are presented in Table 3.

TABLE 3 Pellet Pellet H2 HLMI MI Density Charpy Metallocene (mLb/ (dg/(dg/ (pellets) Mw Mw/ (J @23 C.) Run (Ratio) hr) 10 min) 10 min) (g/cc)(×103) Mn notched 13-1 C + G (2.3) 4 3.96 0.08 0.9497 243 9.9 1.55 13-2C + G (2) 4 7.2 0.12 0.9522 210 16.9 1.56 13-3 C + G (1.9) 4 4.24 0.080.9497 239 9.9 1.94 13-4 C + G (2) 6 5.2 0.12 0.9486 200 15.3 1.64

As is evident, the resins produced according to the present inventionexhibit excellent high impact strength, illustrated by the 23° C.notched charpy impact.

FIG. 4 presents the GPC curves for the resins produced in Run 13-1,13-2, 13-3 and 13-4, demonstrating that a true bimodal molecular weightdistribution polymer is obtained from the catalyst compositions of thisinvention.

In sum, the present invention provides various catalyst compositions,methods for forming a catalyst composition, and resins and pipes formedby using the catalyst compositions. The catalyst composition generallyincludes two metallocene compounds, an activator, and a cocatalyst. Thetwo metallocene compounds are selected such that the two metallocenesproduce polymers having two distinctly different molecular weights. Themetallocenes are combined with an activator-support, an organoaluminumcompound, and an olefin monomer to produce a polyolefin having a bimodalmolecular weight distribution. The resulting polymers have excellentimpact strength. The present invention further provides novelmetallocene compounds and an improved method of synthesis ofhalf-metallocene compounds.

While costly aluminoxanes and organoborates are not required by thepresent invention, they may be used as desired. As demonstrated by theabove examples, the use of a tri-catalyst system, such as thosedescribed herein, produces polyolefin films having a desirably low hazewhile maintaining other physical attributes, such as dart impact.

The foregoing description has been presented for purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise examples or embodiments disclosed.Obvious modifications or variations are possible in light of the aboveteachings. The embodiment or embodiments discussed were chosen anddescribed to provide the best illustration of the principles of theinvention and its practical application to enable one of ordinary skillin the art to utilize the invention in various embodiments and withvarious modifications as are suited to the particular use contemplated.All such modifications and variations are within the scope of theinvention as determined by the appended claims when interpreted inaccordance with the breadth to which they are fairly and legallyentitled.

1-29. (canceled)
 30. A catalyst composition comprising a firstmetallocene compound, a second metallocene compound, and a co-catalyst,wherein: (a) the first metallocene compound has the formula:(X¹)(X²R¹ ₂)(X³)(X⁴)M¹; wherein: (X¹) is cyclopentadienyl, indenyl, orfluorenyl; (X²) is fluorenyl; (X¹) and (X²) are connected by adisubstituted bridging group comprising one atom bonded to both (X¹) and(X²), wherein the atom is carbon or silicon; a first substituent of thedisubstituted bridging group is an aliphatic or aromatic group havingfrom 1 to about 10 carbon atoms; a second substituent of thedisubstituted bridging group is a saturated or unsaturated aliphaticgroup having from 3 to about 10 carbon atoms; R¹ is H or an alkyl grouphaving from 1 to about 4 carbon atoms; (X³) and (X⁴) independently are ahalide; and M¹ is Zr or Hf; and (b) the second metallocene has theformula:

wherein: R² is H or —CH₃; R³ is CH₂═CHCH₂—, CH₂═CH(CH₂)₂—, Ph(CH₂)₃—,CH₃(CH₂—)₃, or H; X⁵ and X⁶ independently are a halide; and M² is Zr orHf.
 31. The composition of claim 30, wherein the co-catalyst comprisesan aluminoxane, an organoboron compound, an ionizing ionic compound, anorganozinc compound, or any combination thereof.
 32. The composition ofclaim 31, further comprising an organoaluminum compound.
 33. Thecomposition of claim 30, wherein a ratio of the first metallocenecompound to the second metallocene compound is in a range from about1:10 to about 10:1.
 34. The composition of claim 30, wherein: the firstsubstituent of the disubstituted bridging group is phenyl or methyl; andthe second substituent of the disubstituted bridging group is butenyl,pentenyl, or hexenyl.
 35. The composition of claim 30, wherein theco-catalyst comprises an aluminoxane.
 36. The composition of claim 30,wherein the co-catalyst comprises an organoboron compound.
 37. Thecomposition of claim 30, wherein the co-catalyst comprises an ionizingionic compound.
 38. A process for polymerizing olefins, the processcomprising contacting the catalyst composition of claim 30 with at leastone olefin monomer under polymerization conditions to produce a polymer.39. The process of claim 38, wherein the catalyst composition iscontacted with ethylene and a comonomer selected from 1-butene,1-pentene, 1-hexene, 1-octene, 1-decene, styrene, or a combinationthereof.
 40. The process of claim 39, wherein the process is a slurrypolymerization process, a gas phase polymerization process, a solutionpolymerization process, or a combination thereof.
 41. The process ofclaim 39, wherein the co-catalyst comprises an aluminoxane, anorganoboron compound, an ionizing ionic compound, an organozinccompound, or any combination thereof.
 42. A catalyst compositioncomprising a first metallocene compound, a second metallocene compound,and a co-catalyst, wherein: (A) the first metallocene compound is:

or any combination thereof; and (B) the second metallocene compound is:

or any combination thereof.
 43. The composition of claim 42, wherein theco-catalyst comprises an aluminoxane.
 44. The composition of claim 42,wherein the co-catalyst comprises an organoboron compound.
 45. Thecomposition of claim 42, wherein the co-catalyst comprises an ionizingionic compound.
 46. A process for polymerizing olefins, the processcomprising contacting the catalyst composition of claim 42 with anolefin monomer and an olefin comonomer under polymerization conditionsto produce a polymer.
 47. The process of claim 46, wherein: the processis a slurry polymerization process, a gas phase polymerization process,a solution polymerization process, or a combination thereof the olefinmonomer is ethylene; and the olefin comonomer comprises 1-butene,1-pentene, 1-hexene, 1-octene, 1-decene, or styrene.
 48. The process ofclaim 47, wherein the co-catalyst comprises an aluminoxane, anorganoboron compound, an ionizing ionic compound, an organozinccompound, or any combination thereof.
 49. A catalyst compositioncomprising a co-catalyst and a metallocene compound having the formula:

wherein: R² is H or —CH₃; R³ is CH₂═CHCH₂—, CH₂═CH(CH₂)₂—, Ph(CH₂)₃—,CH₃(CH₂—)₃, or H; X⁵ and X⁶ independently are a halide; and M² is Zr orHf.
 50. The composition of claim 49, wherein the co-catalyst comprisesan aluminoxane, an organoboron compound, an ionizing ionic compound, anorganozinc compound, or any combination thereof.
 51. A process forpolymerizing olefins, the process comprising contacting the catalystcomposition of claim 49 with at least one olefin monomer underpolymerization conditions to produce a polymer.